Form No: MM0463A

Products that perform...By people who care

INSTALLATION, SCREW
OPERATION & COMPRESSOR
MAINTENANCE AIR
MANUAL COOLED
FLOODED
CHILLERS

MODEL:
AFHX Series R134a
60Hz
TABLE OF CONTENTS

DESCRIPTION PAGE NO DESCRIPTION PAGE NO

1.0 INTRODUCTION 4.4.5.2 Technician status key- main menu ......... 32

1.1 Product Identification. ......................................................... 3 4.4.5.3 Compressor FLA calibration .................. 33
4.4.5.4 To perform sensor calibration ................. 33
2.0 INSTALLATION 4.4.5.5 Manual control ........................................ 33
2.1 General................................................................................... 6 4.4.5.6 Compressor control ................................. 34
2.1.1 Application Precautions ............................................ 6 4.4.5.7 Sensors Override ..................................... 35
2.1.2 Chilled Water Flow ................................................... 6 4.4.6 Control Functions ................................................... 35
2.2 Inspection. ............................................................................. 6 4.4.6.1 Chilled water pump interlock and flow
2.3 Rigging ................................................................................... 6 switch ..................................................... 35
2.3.1 General ...................................................................... 6 4.4.6.2 Customer control interlock ..................... 35
2.3.2 Rigging & Moving .................................................... 6 4.4.6.3 Anti-recycle timer ................................... 36
2.4 Space Requirements and Clearance ................................... 8 4.4.6.4 On delay timer......................................... 36
2.4.1 General ...................................................................... 8 4.4.6.5 Load control ............................................ 36
2.4.2 AFHX ........................................................................ 8 4.4.6.6 Ramp control ........................................... 36
2.5 Foundation .......................................................................... 13 4.4.6.7 Staging control ........................................ 36
2.6 Vibration Isolation.............................................................. 13 4.4.6.8 Modmotor setback control ...................... 36
2.7 Piping connections. ............................................................. 13 4.4.6.9 Sump Heater Control .............................. 36
2.8 Electrical Wiring. ............................................................... 13 4.4.6.10 Suction/ Discharge Pressure Differential
2.9 Controls ............................................................................... 16 control ..................................................... 37
2.9.1 Connections............................................................. 16 4.4.6.11 Evaporator Freeze Shutoff ...................... 37
2.9.2 Settings .................................................................... 16 4.4.6.12 Low pressure cut-off ............................... 37
2.10 Request For Start-Up Representative .............................. 16 4.4.6.13 High pressure cut-off .............................. 37
4.4.6.14 Optical oil level sensor ........................... 37
3.0 OPERATION 4.4.6.15 High oil temperature thermostat ............. 37
3.1 General................................................................................. 17 4.4.6.16 Overload protector .................................. 37
3.2 Unit piping ........................................................................... 17 4.4.6.17 Phase control relay .................................. 37
3.3 System Water Flow Rate ................................................... 17 4.4.6.18 Sensor alarm............................................ 38
3.4 Unit Operation Including Overnight Shut Down and 4.4.6.19 No-stop alarm.......................................... 38
Morning Restart ................................................................. 17 4.4.6.20 Low differential pressure alarm .............. 38
3.4.1 Air Cooled Package Chiller Start-Up ..................... 17 4.5 Condenser Fan Control Logic ........................................... 38
3.5 System Start Up .................................................................. 17 4.5.1 Air-Cooled Condenser Control Setpoints............... 38
3.6 Shut-Down (Overnight Or Weekend) .............................. 22 4.5.2 Increasing Condenser Pressure ............................... 39
3.7 Seasonal Shut-Down Procedure ........................................ 22 4.5.3 Decreasing Condenser Pressure.............................. 39
3.8 Seasonal Start-up Procedure ............................................. 22 4.5.3.1 Adaptive Control Logic .......................... 39
3.9 Safety Relief Valves ............................................................ 22 4.6 Master/ Slave Control Sequence ....................................... 39
3.10 Refrigeration Cycle- Multiple Compressor AFHX ......... 22 4.6.1 Sensor Principle of Operation VIA DBLAN
3.11 Fan Cycling ......................................................................... 23 Communication Bus ............................................... 40
3.12 Liquid Injection .................................................................. 23 4.6.2 Sequence of Operation ............................................ 41
3.13 Hydraulic Capacity Control System................................. 23 4.7 Vision 2020i Local Area Network (DBLAN) ................... 41
4.8 Network Connection Diagram .......................................... 42
4.0 ELECTRICAL 4.9 Hardware Setting ............................................................... 42
4.1 Electrical Data..................................................................... 24 4.9.1 Addressing the Vision 2020i Controller ................. 42
4.2 Wiring Diagram .................................................................. 24 4.9.2 Addressing the Vision 2020i DBG1 Terminal ....... 43
4.3 Typical Operation ............................................................... 24 4.9.3 Vision 2020i Controller LED Status ...................... 44
4.4 Vision 2020i Controller and Terminal ............................. 29
4.4.1 Operator Keypad ....................................................... 29 5.0 MAINTENANCE
4.4.1.1 The fifteen polycarbonate buttons ............... 29 5.1 General ................................................................................ 45
4.4.2 Status Reading ........................................................... 29 5.2 Periodic Inspection ............................................................. 45
4.4.2.1 Input status key ............................................ 29 5.3 Monthly Inspection............................................................. 45
4.4.2.2 Output status key ......................................... 30 5.4 Vessel Maintenance ............................................................ 45
4.4.2.3 Compressor status key ................................. 30 5.4.1 General .................................................................... 45
4.4.2.4 Setpoint key ................................................. 31 5.4.2 Water Side Cleaning Of Evaporator ....................... 45
4.4.2.5 Clock key ..................................................... 31 5.5 Air Cooled Condenser Cleaning ....................................... 45
4.4.2.6 Alarm history key ........................................ 31 5.6 Electrical Malfunction ....................................................... 47
4.4.3 Authorization............................................................. 32 5.7 Refrigerant Charge ............................................................ 47
4.4.3.1 Authorization key ........................................ 32 5.7.1 General .................................................................... 47
4.4.4 Advanced user key and menu ................................... 32 5.7.2 Air Cooled Packages............................................... 47
4.4.4.1 User key ....................................................... 32 5.8 Oil Charge ........................................................................... 47
4.4.5 Technician Key and Menu ...................................... 32 5.9 Troubleshooting .................................................................. 48
4.4.5.1 Technician status key .............................. 32 5.10 Sample Log Sheet ............................................................... 49

SCHEMATIC DIAGRAM, GRAPH AND TABLE

DESCRIPTION PAGE NO DESCRIPTION PAGE NO
Figure 2.3.2 Typical Rigging ......................................................... 7 Figure 4.2 Typical Wiring Schematic ........................................ 25
Figure 2.4.1 Typical Space Requirements ....................................... 8 Figure 4.3.1 Vision 2020i keypad ................................................ 29
Figure 2.4.2 Dimensional Data ...................................................... 10
Figure 2.5A Isolator Location ....................................................... 14 Table 1.1 Physical Specifications ............................................... 5
Figure 2.5B Isolator Point Load Data ........................................... 14 Table 4.4.6.5 Sample Ramp For Several Setpoint (In Minutes)..... 36
Figure 3.2 Typical Piping Schematic ......................................... 18 Table 4.9.3 LED Status ................................................................ 44
Figure 3.3 Evaporator Water Pressure Drop .............................. 21 Table 5.4.2 R134a Pressure/Temperature Properties................... 46

AFHX Standard R134a 60Hz IOM Manual

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1.0 INTRODUCTION

This manual is designed to provide all the necessary information for

installation, operation and maintenance of the latest generation of the
Dunham-Bush horizontal screw compressor air-cooled packaged
chillers.

To use this manual effectively, you must first identify your unit model
from the unit nameplate.

Your Dunham-Bush package has been manufactured under a careful

quality control system. If the package is installed, operated and
maintained with care and attention to the instructions contained herein,
it will give many years of satisfactory service.

It is assumed the user of this manual and those who install, operate and
maintain this equipment are experienced and qualified air conditioning
equipment personnel.

1.1 PRODUCT IDENTIFICATION

A F HX 210 T - 5 S R HR

Air Cooled Chiller HR = Heat Recovery

LN = Low Noise

Flooded Evaporator
Blank = R22
R = R134a
Horizontal Screw Compressor
C = Compact
Nominal Tons H = High Ambient
S = Standard
Q = Special
T = Optional Two
Compressors 5 = 50Hz
Blank = Standard 6 = 60Hz

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1.0 INTRODUCTION

TABLE 1.1 PHYSICAL SPECIFICATIONS

MODEL AFHX 210-6SR 220-6SR 235-6SR 260-6SR 280-6SR 310-6SR

COMPRESSOR

MODEL (QTY) HX 1817 X 1 HX 1709 X 1 HX 1711 X 2 HX 1711 X 1 HX 1811 X 2 HX 1813 X 2

HX 1711 X 1 HX 1811 X 1

RPM 3550 3550 3550 3550 3550 3550

NOMINAL CAPACITY TR 208 220 235 257 280 309

MIN. % UNIT CAPACITY REDUCTION 25% 12.5% 12.5% 12.5% 12.5% 12.5%

EVAPORATOR

MODEL (QTY) L1R (1) D2R (2) J1R (2) J1R (2) K1R (2) K2R (2)

WATER CONNECTOR INCH[MM] 8[203] 8[203] 8[203] 8[203] 8[203] 8[203]

NOM. WATER FLOW / PD GPM / FT IN WG 499/ 14.67 529/ 7.2 565/ 9.63 618/ 11.16 673/ 11.25 743/ 11.53

MIN/ MAX WATER FLOW GPM 159/ 787 235/ 1174 236/ 1174 236/ 1174 257/ 1281 283/ 1409

MIN/ MAX WATER PD FT IN WG. 1.89/ 33.28 1.65/ 30.52 1.96/ 35.56 1.96/ 35.56 1.99/ 36.06 2.02/ 36.77

CONDENSER

COIL ROWS DEEP/ TOTAL FA (SQ.FT) 4/ 282.3 4/ 282.3 4/ 282.3 4/ 141.2, 3/ 188.2 3/ 376.4 4/ 188.2, 3/ 188.2

NO. OF FAN 12 12 12 14 16 16

FAN DIA. MM 800(12) 800(12) 800(12) 860(14) 860(16) 860(16)

MOTOR kWI (QTY) 2.0(12) 2.0(12) 2.0(12) 3.0(14) 3.0(16) 3.0(16)

FLA, AMP (QTY) 3.8(12) 3.8(12) 3.8(12) 4.9(14) 4.9(16) 4.9(16)

TOTAL CFM 157500 156177 153594 230034 265944 257460

MIN. AMBIENT TEMP. (F) AT MIN. LOAD 45 45 45 45 45 45

ELECTRICAL

NOM. VOLTAGE 460/3/60 460/3/60 460/3/60 460/3/60 460/3/60 460/3/60

UNT RLA A 341.3 366.5 394.5 449.8 488.5 508.3

UNIT MAX. INRUSH A 530.1 416.2 444.2 494.5 524.3 653.1

GENERAL

UNIT LENGTH INCH[MM] 276[7010] 276[7010] 276[7010] 318[8077] 360[9144] 381[9677]

UNIT WIDTH INCH[MM] 88[2235] 88[2235] 88[2235] 88[2235] 88[2235] 88[2235]

UNIT HEIGHT INCH[MM] 96.5[2451] 96.5[2451] 96.5[2451] 96.5[2451] 96.5[2451] 96.5[2451]

SHIPPING WEIGHT LBS[KG] 17199[7801] 18690[8478] 19596[8889] 21328[9674] 23645[10725] 25162[11413]

OPERATING WEIGHT LBS[KG] 17542[7957] 19107[8667] 20099[9117] 21831[9827] 24205[10979] 25768[11688]

OPERATING CHARGE R134a LBS[KG] 567[257] 600[272] 642[291] 703[319] 794[360] 877[398]

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1.0 INTRODUCTION

MODEL AFHX 355-6SR 405-6SR 435-6SR 460-6SR 515-6SR 555-6SR

COMPRESSOR

MODEL (QTY) HX 1813 X 1 HX 1816 X 2 HX 1817 X 2 HX 1813 X 3 HX 1816 X 1 HX 1816 X 2

HX 1816 X 1 HX 1813 X 2 HX 1813 X 1

RPM 3550 3550 3550 3550 3550 3550

NOMINAL CAPACITY TR 355 402 434 460 512 557

MIN. % UNIT CAPACITY REDUCTION 12.5% 12.5% 12.5% 8.33% 8.33% 8.33%

EVAPORATOR

MODEL (QTY) L2R (2) L3R (2) M1R (2) L2R (1), M2R (1) L3R (1), M2R (1) L3R (1), M3R (1)

WATER CONNECTOR INCH[MM] 10[254] 10[254] 12[305] 12[305] 12[305] 12[305]

NOM. WATER FLOW / PD GPM / FT IN WG 852/ 9.02 966/ 10.03 1042/ 9.17 1104/ 11.89 1231/ 14.45 1337/ 14.95

MIN/ MAX WATER FLOW GPM 365/ 1810 390/ 1948 436/ 2173 411/ 2040 423/ 2109 439/ 2184

MIN/ MAX WATER PD FT IN WG. 1.96/ 35.14 1.96/ 35.59 1.93/ 34.47 1.95/ 34.81 1.94/ 35.04 1.97/ 35.22

CONDENSER

COIL ROWS DEEP/ TOTAL FA (SQ.FT) 4/ 188.2, 3/ 235.3 4/ 235.3, 3/ 235.3 4/ 470.6 3/ 256.7, 4/ 385 4/ 641.7 4/ 641.7

NO. OF FAN 18 20 20 20 20 20

FAN DIA. MM 860(18) 860(20) 860(20) 860(20) 860(20) 860(20)

MOTOR kWI (QTY) 3.0(18) 3.0(20) 3.0(20) 3.0(20) 4.0(20) 4.0(20)

FLA, AMP (QTY) 4.9(18) 4.9(20) 4.9(20) 4.9(20) 6.5(20) 6.5(20)

TOTAL CFM 289863 316260 309225 347340 381612 373422

MIN. AMBIENT TEMP. (F) AT MIN. LOAD 45 45 45 45 45 45

ELECTRICAL

NOM. VOLTAGE 460/3/60 460/3/60 460/3/60 460/3/60 460/3/60 460/3/60

UNIT RLA A 585.4 655.8 695.7 755.4 827.8 896.9

UNIT MAX. INRUSH A 726.7 781.4 883.7 896 974.7 1023.6

GENERAL

UNIT LENGTH INCH[MM] 423[10744] 465[11811] 465[11811] 444[11278] 444[11278] 444[11278]

UNIT WIDTH INCH[MM] 88[2235] 88[2235] 88[2235] 88[2235] 88[2235] 88[2235]

UNIT HEIGHT INCH[MM] 96.5[2451] 96.5[2451] 96.5[2451] 120.5[3061] 120.5[3061] 120.5[3061]

SHIPPING WEIGHT LBS[KG] 27977[12690] 32270[14637] 33567[15226] 34716[15747] 36759[16673] 37994[17234]

OPERATING WEIGHT LBS[KG] 28749[13040] 33091[15010] 34492[15646] 35582[16140] 37648[17077] 38912[17651]

OPERATING CHARGE R134a LBS[KG] 1005[456] 1140[517] 1228[557] 1303[591] 1453[659] 1576[715]

AFHX Standard R134a 60Hz IOM Manual

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2.0 INSTALLATION

2.1 GENERAL 1.) Check all crates and cartons received against
the Bill of Lading/ Shipping Papers to be sure
Packaged chillers are designed to cool water or
they agree.
other non-corrosive liquids. The liquid to be
cooled is to be circulated through the tubes of a 2.) Check the model number and the electrical
refrigerant evaporator where the temperature is characteristics on the nameplate to determine
reduced to the desired level. The heat absorbed by if they are correct.
the refrigerant in the evaporator is rejected via the 3.) Check for freight damage, shortages or other
condenser where it raises the temperature of discrepancies and note them on the delivery
another liquid stream (usually water) being receipt before signing.
circulated through the tubes. This heat is usually In the event that any damage is found, a damage
rejected by a cooling tower or closed circuit claim should immediately be filed by the
cooled. purchaser against the delivering carrier as all
Care should be taken to see that the equipment is shipments are F.O.B. Factory.
properly installed and adjusted. An installer or
operator should first become familiar with the
information contained in this manual.
2.3 RIGGING
2.1.1 APPLICATION PRECAUTIONS 2.3.1 GENERAL
The following instructions are intended to Each unit has been carefully tested and
help assure proper and successful crafted at the factory where every
application of your water chilling machine. precaution is taken to assure that the unit
reaches you in perfect condition. It is very
2.1.2 CHILLED WATER FLOW important that the riggers and movers
The Dunham-Bush AFHX Packaged should use the same care and precaution in
Water Chiller is designed for a constant moving the equipment into place. Make
chilled water flow rate, even when the sure that chains, cables. or other moving
cooling load is varying. The machine will equipment are placed so as to avoid
generally perform satisfactorily with damage to the unit or piping. The
steady flow rates deviating from design by refrigerant piping must not be used as a
as much as 10%. However, varying water ladder or as a handhold. Do not attach a
flow rates can cause control instability chain hoist sling to the piping or
which will result in undesirable system equipment. Move the unit in an upright
effects, particularly poor control of leaving position and let it down gently from trucks
chilled water temperature. If two-way or rollers.
valves are used to control flow through
cooling coils, some means such as an 2.3.2 RIGGING AND MOVING
automatic modulating valve should be Any unit mounted on skids may be moved
provided in the system to maintain steady
with a forklift, but care must be taken not
flow through the evaporator.
to damage the unit with forks. The skids
If the chilled water system is arranged for should not be removed until the unit is at
the dual purpose of cooling and heating, its final location.
the evaporator must incorporate valves to
prevent the flow of hot water through it. The AFHX model is to be rigged through
This can be done with either manual or the holes in the base side rails. In all cases,
automatic shutoff valves, but the method spreader bars must be used between
of control must be that water temperature rigging lines to prevent coil or fan deck
entering the evaporator never exceeds damage. The unit must be lifted using All
90F[32.2C]. Rigging Points. Refer to Rigging
Instructions on Figure 2.3.2.
All models can be pushed or pulled (with
2.2 INSPECTION chains) from the control box end only.
When the equipment is delivered, it is important Truck forks must be kept level and not
that the following inspection be completed in the tilted back. Do not raise the end of the unit
presence of the carrier's representative. more than 2"[51mm] off the floor.

AFHX Standard R134a 60Hz IOM Manual

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2.0 INSTALLATION

FIGURE 2.3.2 TYPICAL RIGGING

AFHX Standard R134a 60Hz IOM Manual

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2.0 INSTALLATION

2.4 SPACE REQUIREMENTS the condenser, and removal of heated air

from the condenser area. Where this
AND CLEARANCE essential requirement is not provided, it
will result in higher condensing
2.4.1 GENERAL temperatures, which cause poor
The dimensional data and clearances that operation, higher power consumption and
follow are useful for determining space possibly, eventual failure of equipment.
requirements. The unit should be placed Units must not be located in the vicinity
to make the clearance noted available for of steam, hot air or fume exhausts.
servicing properly. Failure to allow these Another consideration which must be
clearances will cause serious trouble and taken into account is that the unit should
result in higher costs for operation, be mounted away from noise sensitive
maintenance and repair. spaces and must have adequate support to
avoid vibration and noise transmission
2.4.2 AFHX into the building. Units should be
The dimensional data are shown in mounted over corridors, utility areas, rest
Figure 2.4.2 and space requirements are rooms or other auxiliary areas where
shown in Figure 2.4.1. The most sound levels are not an important factor.
important consideration which must be Sound and structural consultants should
taken into account when deciding upon be retained for recommendations on
location of air-cooled equipment, is critical installations.
provision for a supply of ambient air to

FIGURE 2.4.1 TYPICAL SPACE REQUIREMENTS

WALLS OR OBSTRUCTIONS

The unit should be located so that air may circulate freely and not be recirculated. For proper airflow
and access all sides of the unit must be a minimum of eight feet [2438mm] away from any wall or
obstruction. It is preferred that this distance be increased whenever possible. Care should be taken to
see that ample room is left for maintenance work through access doors and panels. Overhead
obstructions are not permitted. When the unit is in an area where it is enclosed by three walls the unit
must be installed as indicated for units in a pit.

AFHX Standard R134a 60Hz IOM Manual

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2.0 INSTALLATION

FIGURE 2.4.1 TYPICAL SPACE REQUIREMENTS

Single Pit (See Note 2)

Double Pit (See Note 2)

Multi Pit

Notes:
1.) All dimensions are minimal, unless
otherwise noted.
Corner Wall
2.) Pit installations are not re-
commended. Re-circulation of hot
condenser air in combination with
surface air turbulence cannot be
predicted. Hot air re-circulation will
severely affect unit efficiency (EER)
and can cause high pressure or fan
motor temperature trips. Dunham-
Bush will not be responsible for
ducting fans to a higher level to
alleviate the above mentioned
conditions.

AFHX Standard R134a 60Hz IOM Manual

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2.0 INSTALLATION

FIGURE 2.4.2 DIMENSIONAL DATA

AFHX 210-6SR

AFHX 220-6SR, 235-6SR

AFHX 260-6SR

NOTE : ALL DIMENSIONS ARE IN INCHES(MM).

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2.0 INSTALLATION

AFHX 280-6SR

AFHX 310-6SR

AFHX 355-6SR

NOTE : ALL DIMENSIONS ARE IN INCHES(MM).

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2.0 INSTALLATION

AFHX 405-6SR, 435-6SR

AFHX 460-6SR, 515-6SR, 555-6SR

NOTE : ALL DIMENSIONS ARE IN INCHES(MM).

AFHX Standard R134a 60Hz IOM Manual

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2.0 INSTALLATION

2.5 FOUNDATION removable access panel at the end of the unit.

Opening the hole to the left-hand side of the panel
Refer to index for unit dimensions and load
so that it can still be removed after piping is in
points. Foundations must be level for proper
place. Holes can also be cut down through the
operation and functioning of controls and
floor of the unit providing no cross-members are
provision must be made for supporting the
cut out. Install air vent points to permit complete
individual load points as shown in the unit
air purging of the chilled water circuit. Install
dimensions. Roof mounted units must be
drain valves in similar low points to facilitate
supported on adequate steel structure. If units are
complete water system drainage. Install
located on the ground level, a concrete base is
temperature & pressure indicators in the water
recommended.
piping at the unit to monitor water flow. Install
shut-off valves to isolate the unit from the piping
system during unit servicing.
2.6 VIBRATION ISOLATION Note: Due to possible high pressures resulting
Under certain critical conditions. It may be from rising temperatures, do not close shut-off
necessary to install vibration isolators under the valves with cold water in the evaporator.
base of the Packaged Chiller. It is important that the chilled water system be
Rubber-in-shear or spring vibration isolators are cleaned before startup to avoid collecting debris
offered as optional items. When spring isolators in the evaporator. After filling the system with
are used, flexible connections must be installed in water (or a glycol solution), start pump, bleed off
the water piping system and in the refrigerant trapped air, and check for proper flow rate by
lines of split systems. Note: These flexible measuring water pressure drop across evaporator.
connectors must be suitable for the fluid and
pressures involved.
All piping which is external to the packaged 2.8 ELECTRICAL WIRING
chiller must be supported by spring mounted
hangers and any piping which goes through the In connecting power wiring to the unit, the
wall, ceiling or floor should be properly sheathed following precautions should be taken:
to prevent transmission of piping vibration to the 1.) All field wiring is to be in accordance with
structure. the National Electric Code and must comply
When spring isolators are used, electrical service with state and local codes. See Electrical Data
to the unit must also be flexibly connected. By for minimum circuit ampacity and fuse size.
means of a 36" section of flexible conduit. 2.) Check unit wiring for damage and all terminal
connections for tightness. Unit terminal
blocks are to be connected with copper
conductors only, sized per ampacity listed on
2.7 PIPING CONNECTIONS
unit data plate.
Refer to the dimensional drawings for water
3.) Connections to unit should match the unit
piping connection locations. After the unit has
nameplate in volts, phase, and Hertz. Voltage
been leveled and isolators (if any) installed &
must not vary beyond 10% of nameplate
adjusted, connect evaporator water piping,
value and voltage imbalance between phases
keeping in mind that the evaporator tubes may
must not exceed 2% at any time during
require cleaning or replacement at some future
operation of the unit.
date, and removable sections of piping will be
required to permit evaporator head removal. 4.) Phase sequence to connectors L1, L2 and L3
Piping must be supported to avoid excess stress shall be in that order. Check with Amprobe
on the evaporator heads. Cut piping holes in the phase sequence adapter PSA-1 or equivalent.

AFHX Standard R134a 60Hz IOM Manual

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2.0 INSTALLATION

FIGURE 2.5 ISOLATOR LOCATION AND POINT LOAD DATA

1.) AFHX 210-6SR, 220-6SR, 235-6SR, 260-6SR

2.) AFHX 280-6SR, 310-6SR

a.) Point Load Location Inches [mm]

Unit Model
A Dim. B Dim. C Dim. D Dim. E Dim. F Dim.
AFHX

210-6SR 86 [2184] 21 [533] 117 [2972] 117 [2972] 21 [533] -

220-6SR 86 [2184] 21 [533] 117 [2972] 117 [2972] 21 [533] -
235-6SR 86 [2184] 21 [533] 117 [2972] 117 [2972] 21 [533] -
260-6SR 86 [2184] 21 [533] 138 [3505] 138 [3505] 21 [533] -
280-6SR 86 [2184] 28 [711] 101 [2565] 102 [2591] 101 [2565] 28 [2565]
310-6SR 86 [2184] 33 [839] 105 [2667] 105 [2667] 105 [2667] 33 [839]

b.) Point Load Data lbs [kg]

Unit Model Total Operating
Pos. #1 Pos. #2 Pos. #3 Pos. #4 Pos. #5 Pos. #6 Pos. #7 Pos. #8
AFHX Weight

210-6SR 2414 [1095] 2652 [1203] 2890 [1311] 3067 [1391] 3195 [1449] 3323 [1507] - - 17542 [7957]
220-6SR 3092 [1403] 3179 [1442] 3265 [1481] 3258 [1478] 3190 [1447] 3123 [1417] - - 19107 [8667]
235-6SR 3272 [1484] 3330 [1511] 3389 [1537] 3428 [1555] 3370 [1529] 3311 [1502] - - 20099 [9117]
260-6SR 3733 [1694] 3667 [1663] 3600 [1633] 3506 [1591] 3610 [1638] 3714 [1685] - - 21831 [9903]
280-6SR 3272 [1484] 3098 [1405] 2924 [1326] 2749 [1247] 2779 [1261] 2953 [1340] 3128 [1419] 3302 [1498] 24205 [10979]
310-6SR 3412 [1548] 3275 [1486] 3137 [1423] 3000 [1361] 3030 [1374] 3167 [1437] 3304 [1499] 3442 [1561] 25768 [11688]

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2.0 INSTALLATION

3.) AFHX 355-6SR, 405-6SR, 435-6SR, 460-6SR, 515-6SR, 555-6SR

a.) Point Load Location Inches [mm]

Unit Model
A Dim. B Dim. C Dim. D Dim. E Dim. F Dim. G Dim. H Dim.
AFHX

355-6SR 86 [2184] 40.75 [1035] 68.25 [1734] 68.25 [1734] 68.5 [1740] 68.25 [1734] 68.25 [1734] 40.75 [1035]

405-6SR 86 [2184] 40.75 [1035] 76.5 [1944] 76.5 [1943] 77.5 [1969] 76.5 [1943] 76.5 [1943] 40.75 [1035]

435-6SR 86 [2184] 40.75 [1035] 76.5 [1944] 76.5 [1943] 77.5 [1969] 76.5 [1943] 76.5 [1943] 40.75 [1035]

460-6SR 86 [2184] 40.75 [1035] 72.5 [1842] 72.5 [1842] 72.5 [1842] 72.5 [1842] 72.5 [1842] 40.75 [1035]

515-6SR 86 [2184] 40.75 [1035] 72.5 [1842] 72.5 [1842] 72.5 [1842] 72.5 [1842] 72.5 [1842] 40.75 [1035]

555-6SR 86 [2184] 40.75 [1035] 72.5 [1842] 72.5 [1842] 72.5 [1842] 72.5 [1842] 72.5 [1842] 40.75 [1035]

b.) Point Load Data lbs [kg]

Total
Unit Model Pos. Pos. Pos. Pos. Pos. Pos. Pos. Pos. Pos. Pos. Pos. Pos.
Operating
AFHX #1 #2 #3 #4 #5 #6 #7 #8 #9 #10 #11 #12
Weight

2437 2393 2350 2307 2264 2220 2234 2326 2417 2509 2600 2692 28749
355-6SR
[1105] [1086] [1066] [1046] [1027] [1007] [1013] [1055] [1096] [1138] [1179] [1221] [13040]

2810 2781 2752 2723 2694 2665 2705 2734 2763 2792 2821 2850 33091
405-6SR
[1275] [1262] [1249] [1235] [1222] [1209] [1227] [1240] [1253] [1266] [1280] [1293] [15010]

2974 2926 2878 2831 2783 2735 2745 2823 2870 2918 2966 3013 34492
435-6SR
[1349] [1327] [1306] [1284] [1262] [1241] [1259] [1280] [1302] [1324] [1345] [1367] [15646]

2937 2938 2939 2940 2941 2942 2999 2996 2992 2989 2986 2983 35582
460-6SR
[1332] [1333] [1333] [1334] [1334] [1335] [1360] [1359] [1357] [1356] [1354] [1353] [16140]

2984 3035 3086 3137 3188 3240 3296 3243 3190 3136 3083 3030 37648
515-6SR
[1354] [1377] [1400] [1423] [1446] [1470] [1495] [1471] [1447] [1423] [1398] [1374] [17077]

3368 3308 3247 3187 3126 3066 3122 3181 3239 3297 3356 3414 38912
555-6SR
[1528] [1500] [1473] [1446] [1418] [1391] [1416] [1443] [1469] [1496] [1522] [1549] [17651]

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2.0 INSTALLATION

2.9 CONTROLS 2.10 REQUEST FOR START-

UP REPRESENTATIVE
2.9.1 CONNECTIONS
Controls which are to be field installed After the installation has been completed and
should be connected in accordance with checked, Form 9180 must be filled out and sent to
the appropriate wiring diagram the Dunham-Bush Service Department for
accompanying the unit. The following authorized start-up representative to perform the
connections should be made where initial start-up of the Dunham-Bush packaged
applicable: chiller. The purchaser will have competent
1.) Connect a set of normally open service and operating personnel in attendance to
auxiliary contacts from chilled water assist in the work involved, and also to be trained
pump contactor into unit controls as in the service and maintenance of this unit.
shown on unit wiring diagram. (During the warranty period, the manufacturer is
2.) Install a chilled water flow switch responsible for parts only upon proof of defective
(paddle type recommended) (or workmanship or manufacture).
differential pressure switch) in straight
length of chilled water piping to avoid Following receipt of the signed Form 9180, a
turbulence. Connect in same electrical representative will be sent to the customer. He
circuit as ( 1.) will inspect the installation to determine whether
it meets Dunham-Bush, Inc. requirements;
perform the initial start-up of the installation;
2.9.2 SETTINGS
determine whether it is in satisfactory operating
All controls are factory set, however condition; and instruct the specified customer
operating control settings are not always personnel in its operation and maintenance for the
applicable under all operating conditions. length of time specified in the purchase contract.
For recommended control settings, see
wiring diagram accompanying unit. Safety
controls must be set to factory NOTE: Sump oil heaters should be energized for
recommendations. a minimum of 24 hours and the oil sump
temperature must be at a minimum of
100F [38C] prior to arrival of start-up
NOTE: WATER QUALITY - AFHX
representative. This will ensure that the
Evaporators used in these packages are oil is warm enough to vaporize any
made of steel, copper and brass and are dissolved refrigerant and that the oil is
suitable for operation with well-
within the normal operating temperature
maintained water systems. However, if
range.
the water used in evaporator is corrosive,
high in mineral content or entrained
solids, the water can cause reduced WARNING: The compressor(s) should be
performance and even failure of heat started initially ONLY under the
exchangers. Therefore, it may be direct supervision of an Authorized
necessary to obtain the services of a Dunham-Bush, Inc., Start-Up
water treatment consultant and to Representative.
provide and maintain water treatment.
This is particularly important with glycol
systems.

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3.0 OPERATION

3.1 GENERAL pump contacts to start & stop this unit. These are
safety controls, not operational controls.
The unit should be started up only by a
refrigeration technician who is familiar with
3.4.1 AIR COOLED PACKAGE
accepted operation practices for refrigeration
systems. CHILLER START-UP
Use small screw unit start-up report to record all The unit is ready for start-up when the
temperature, pressure, electrical readings and following procedures have been
control settings. A copy must be forwarded to completed.
Dunham-Bush, Inc., before the warranty will be 1. Water piping for the evaporator is
honored. installed and tested.
2. Electrical connections are made and
properly fused.
3.2 UNIT PIPING 3. Unit has been leak tested. Leaks
Each unit has a separate refrigerant circuit for corrected, and charge completed.
each compressor. See Figure 3.2 for typical unit 4. Compressor crankcase heater(s) has
piping schematic. been energized for a minimum of 24
hours.
5. Calibrated refrigerant gages have been
3.3 SYSTEM WATER FLOW connected to the suction and discharge.
RATE 6. Turn on the chilled water pump, check
The quantity of chilled water being circulated can direction of rotation and adjust the
be measured quite accurately (5%) by water flow through the evaporator to
determining the water pressure drop through the the specified flow rate. Bleed off all
evaporator and reading GPM [m/hr] from the entrained air.
evaporator pressure drop curve, Figure 3.3. 7. Manually energize the fan starters and
Connect reliable pressure gauges to valves check the fan rotation. Fans should pull
installed in evaporator entering and leaving water air through the condenser coil and
vent connections and read pressure difference discharge vertically upwards.
with chilled water pump in operation. An 8. Check all refrigerant valves to be sure
alternative method of determining GPM [m/hr] is they are open.
to measure pressure difference from pump inlet to 9. Proceed to System Start-up.
outlet and read GPM [m/hr] from pump curve. Compressor #1 will start in about 15
However due to the quality of water at the jobsite, minutes & proceed to load up if leaving
the accuracy of the curve might vary. Conditions water temperature is above setpoint.
such as water hardness, organic material, Compressor #2 will follow as the demand
suspended solids and water velocity may dictates.
contribute to a greater fouling. The quality of the
water could be maintained by chemical treatment
and periodical cleaning. The curve plotted is 3.5 SYSTEM START UP
based on a clean water system. 1. Before starting the compressor(s), check all
three phases of supply voltage, of all legs of
the motor. They must be within 10% of the
3.4 UNIT OPERATION nameplate voltage. Check to be sure
INCLUDING OVERNIGHT compressor is not running backwards.
SHUT-DOWN AND 2. Start compressor(s), check the gages and note
MORNING RESTART if the pressures are within the prescribed
Caution: These units may equipped with limits.
manifold installed manual discharge valve that 3. Stage unit down until all compressors are off
must be opened before attempting to start. and check the compressor crankcase sight
Important: Do not use chilled water pump glass for oil level. It should be 1/2 to 3/4 of the
operation via the flow switch or Aux chilled water compressor sight glass.

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3.0 OPERATION

FIGURE 3.2 TYPICAL PIPING SCHEMATIC

1.) 1 Compressor, 1 Evaporator

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3.0 OPERATION

2.) 2 Compressors, 2 Evaporators

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3.0 OPERATION

3.) 3 Compressors, 2 Evaporators

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3.0 OPERATION

FIGURE 3.3 EVAPORATOR WATER PRESSURE DROP

AFHX 210-6SR
AFHX 220-6SR
AFHX 235-6SR
AFHX 260-6SR
AFHX 280-6SR
AFHX 310-6SR
AFHX 355-6SR
AFHX 405-6SR
AFHX 435-6SR
AFHX 460-6SR AFHX 555-6SR
AFHX 515-6SR

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3.0 OPERATION

4. The electrical control settings should be operating season or every 6 months if the unit
checked and if necessary, reset to those is used year round
settings indicated on the wiring diagram. The power supply to the unit may be de-
Safety controls are factory set and must be energized to conserve energy. Just remember
maintained at settings indicated on the wiring that all heaters will now be inactive, and the
diagram. evaporator could freeze-up if not properly
5. The temperatures of the chilled water both in drained.
and out, should be checked to insure the unit is
operating within the desired temperatures.
3.8 SEASONAL START-UP
PROCEDURE
3.6 SHUT-DOWN (OVERNIGHT l. Check fan drives for wear, rust, propeller
OR WEEKEND) clearance, etc. and make necessary repairs &
adjustments. Grease main fan shaft bearings
To shut down in the unit with compressors on or
with a good grade of EP ball bearing grease.
off, turn each individual compressor switch. Do
not close any valve. The chilled water pump shall 2. Check & clean condenser fin surface if
then be turned off. Finally, do not open the main necessary. Use a warm water soap solution,
unit disconnect. Main power is required to keep being careful not to bend fins. Comb out bent
the sump heaters. fin areas.
3. Check all power supply connections at all
Important: Discontinue chilled water points, and all control terminal screws for
pump operation when unit is not tightness.
operational.
4. Energize main power to unit & leave on for at
Note: For chillers operating in low least 24 hours in order for compressors to
ambient, if it is possible that the overnight thoroughly warm up.
ambient will drop below 45F [7C], it is 5. Start chilled water pump and verify correct
preferable to leave the chilled water pump flow-rate glycol % if required. Bleed-off
on. system air if necessary.
6. Open main discharge valve in discharge
header.
3.7 SEASONAL SHUT-DOWN 7. Open liquid valve on sealpot.
PROCEDURE 8. Turn control circuit power switch on, and all
individual compressor circuit switches. Press
Standard Ambient Units computer keyboard reset key (RST).
1. Follow standard overnight shutdown procedure Compressors should start after start-up clock
2. Turn off chilled water pump times out and will come on in sequence to
3. Close manual discharge valve satisfy the existing load.
4. Close liquid valve on sealpot
5. If ambient temperature during the extended 3.9 SAFETY RELIEF VALVES
shut-down period will not get below freezing, Each pressure vessel is protected by a safety relief
the chilled water system may be left filled, If valve as required by ASME Code. Each
the ambient temperature will be below compressor is protected by a relief valve which is
freezing, drain all water thoroughly, removing vented to atmosphere. Never install any kind of
all vent & drain plugs from both heads of the shut-off valve in a safety relief vent line.
evaporator, and blow out tubes will
compressed air to avoid serious stagnant water
corrosion. 3.10 REFRIGERATION CYCLE
6. Finally, it is recommended that an oil sample -MULTIPLE COMPRESSOR
be taken from each compressor & submitted AFHX
for lab analysis. Dunham-Bush offers this Following is the normal sequence of operation for
service in its "Oil Kare" program. This a unit installed in a typical air conditioning
analysis should be done at the end of each system. Refer to Figure 3.2, the typical piping
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3.0 OPERATION

schematic for multiple compressor AFHX unit. system designed to feed refrigerant liquid into the
Each horizontal screw compressor discharges hot, compressor to provide additional motor cooling as
high pressure gas into a hot gas manifold through required. The liquid injection control the
an oil separator and is then split and routed into compressor discharge gas temperature below
the left-hand and right-hand side condenser where 158F[70C], the maximum discharge operating
it condenses, rejecting heat to the outdoor air temperature of these compressors.
drawn through the coil by fans. The liquid
refrigerant from the condenser is drain out from
bottom of the condenser coil through liquid stop
3.13 HYDRAULIC CAPACITY
valve into the economizer feed line.
The refrigerant flows through the economizer CONTROL SYSTEM
feed ball valve, dropping its pressure, causing it to Each compressor has a hydraulic control system
flash. It then flows into the flash economizer tank to supply the proper force necessary to actuate the
which is at an intermediate pressure between slide valve, thereby regulating compressor
condenser and evaporator Liquid is centrifugally loading for maximum unit capacity. It is
separated from the flash gas and the liquid drains composed of a normally closed solenoid valve
to the bottom of the tank, exits via the economizer (SV1), a normally closed solenoid valve (SV2), a
drain line, and passes through the economizer slide valve, rod, cylinder and piston. The slide
drain ball valve. Both economizer ball valves are valve and the piston are connected by the rod.
actuated by a Modutrol motor that adjusts flow to During start up, valve SV1 is energized while
maintain an appropriate refrigerant level in the valve SV2 is not energized. There will not be a
evaporator, determined by a liquid level float sufficient oil pressure in the cylinder to overcome
switch. the opposing spring force. This starting position
From the drain line, liquid refrigerant flows into of the side valve allows the maximum amount of
the flooded evaporator, where it boils, cooling the refrigerant to bypass the compression chamber i.e
water flowing inside evaporator tubes. Vapor 25% of full load. This minimum load will require
from the boiling refrigerant flows up the suction low starting current which is important in
pipes through a shut-off valve (optional), suction protecting the compressor motor. When loading,
check valve and suction filter (inside compressor) valve SV1 is not energized while valve SV2 is
into the compressor where it is compressed and energized. Oil will flow into the cylinder, building
starts the cycle again. sufficient pressure to overcome the opposing
Vapor flows from the top of flash economizer into spring force causing the slide valve moving to the
the compressor at the vapor injection port, which right. This will increase the effective compression
feeds it into the compressor part way through the volume in the compression chamber and hence
compression process. Check valve prevents the refrigeration flow rate. As a result,
backflow at shutdown in multi-compressor units. refrigeration capacity increases. When the
All compressors operate in parallel on a common compressor is given a hold command, valve SV1
evaporator and condenser. and SV2 are not energized. This will prevent oil
flow into or out of the cylinder causing the piston
to halt. During unloading, valve SV1 is energized
while valve SV2 is not energized. The spring
3.11 FAN CYCLING force will cause oil to bleed from the cylinder and
On start-up, all fan will remain off (some units push the slide valve towards its original position.
may have base fans which run together with
compressor). As the head pressure builds up, next
fan stage will start. Subsequently fan stage will SOLENOID
VALVE 1
SOLENOID
VALVE 2
start if the head pressure continues to rise. Refer
wiring circuit diagram for number of fan stage. Start Energize Not Energize

Loading Not Energize Energize

3.12 LIQUID INJECTION Unloading Energize Not Energize

Each compressor is fitted with a liquid injection Stable Not Energize Not Energize

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4.0 ELECTRICAL

4.1 ELECTRICAL DATA

COMPRESSOR DATA COND. FAN MOTOR DATA UNIT ELECTRICAL DATA
AFHX
MODEL
MODEL QTY RLA LRA QTY HP FLA FLA MCA MFS

210-6SR HX1817 1 296 1635 12 2 4.3 348 422 700

HX1709 1 149 730 6 2 4.3

220-6SR 378 422 500
HX1711 1 177 845 6 2 4.3

HX1711 1 177 845 6 2 4.3

235-6SR 406 450 600
HX1711 1 177 845 6 2 4.3

HX1711 1 177 845 6 3 5.5

260-6SR 459 510 700
HX1811 1 205 915 8 3 5.5

HX1811 1 205 915 8 3 5.5

280-6SR 498 549 700
HX1811 1 205 915 8 3 5.5

HX1813 1 217 1400 8 3 5.5

310-6SR 522 576 700
HX1813 1 217 1400 8 3 5.5

HX1813 1 217 1400 8 3 5.5

355-6SR 597 667 800
HX1816 1 281 1495 10 3 5.5

HX1816 1 281 1495 10 3 5.5

405-6SR 672 742 1000
HX1816 1 281 1495 10 3 5.5

HX1817 1 296 1635 10 3 5.5

435-6SR 702 776 1000
HX1817 1 296 1635 10 3 5.5

HX1813 1 217 1400 8 3 5.5

460-6SR 761 815 1000
HX1813 2 217 1400 12 3 5.5

HX1816 1 281 1495 8 4 7.1

515-6SR 857 927 1200
HX1813 2 217 1400 12 4 7.1

HX1816 1 281 1495

8 4 7.1
555-6SR HX1816 1 281 1495 921 991 1200
12 4 7.1
HX1813 1 217 1400

NOTES: MCA MINIMUM CIRCUIT AMPACITY

MFS MAXIMUM FUSE SIZE
RLA - RATED LOAD AMPS AT ARI CONDITIONS
INR INRUSH AMPS
LRA - LOCKED ROTOR AMPS

4.2 WIRING DIAGRAM - power has been on the controller for 15 minutes
- all safety conditions satisfied
Figure 4.2 are wiring diagrams for 2-compressor
- leaving chilled water temperature 2F [1.1C]
unit control by Vision 2020i controller. This may
or more above setpoint
not be an accurate representation of your unit. It is
best to use the wiring diagram mounted in the A compressor is started by first energizing 1MC
package control panel. A copy of that diagram is followed by 1DC and 1SC. Anti-recycle time of
furnished with the unit owners manual. 15 minutes is initiated within the computer at
start.
When the compressor starts, the controller
4.3 TYPICAL OPERATION monitors amperage by means of 1CT, voltage
In order to start a compressor, the following using 3T, leaving water temperature using TS,
conditions must be met: and condensing pressure. These inputs are used to
- system voltage above phase control relay (PCR) control the loading and staging of the compressor.
setting The compressor's loading is controlled by pulsing
- chilled water pump running signals to the load and unload solenoids.
- chilled water flow switch made To shut down the unit automatically, the customer
- compressor circuit breakers on control contacts must be opened. To shut down
- customer unit control contact closed the unit manually, simply shut off the compressor
- control switch and compressor switches on switches. This will cause a no-run alarm that must
- reset pressed on controller keypad be reset to restart the compressor.

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4.0 ELECTRICAL

FIGURE 4.2 TYPICAL WIRING DIAGRAM 2 Compressors

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4.0 ELECTRICAL

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4.0 ELECTRICAL

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4.0 ELECTRICAL

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4.0 ELECTRICAL

4.4 VISION 2020i 4.4.1.1 The fifteen polycarbonate buttons:

CONTROLLER AND a) Seven polycarbonate buttons at top
TERMINAL row
Button Description
Vision 2020i controller is equipped with a user
friendly 132x64 pixels back-lit graphic display Displays the analog inputs and
INPUT STATUS digital inputs status measured by
terminal. It is connected with controller through the probes/sensors.
telephone cable. This terminal allows carrying out
OUTPUT Displays the relay outputs and
all program operations. The user terminal allows STATUS analog outputs status.
displaying the unit working conditions,
compressor run times, alarm history at any time COMPRESSOR Displays the status of Compressor
1, 2 and so on.
and modifying the parameters. The terminal also STATUS

has an automatically self-test of the controller on

system start-up. Multiple messages will be SETPOINT Displays the status of set points.

displayed by automatically scrolling from each

message to the next. All of these messages are CLOCK/
Displays the date, time and day.
SCHEDULE
spelled out in English language on the LCD
screen.
ALARM HISTORY Display the alarm history.

4.4.1 OPERATOR KEYPAD AUTHORIZATION To log in the level of passwords.

The operator keypad consists of 15

polycarbonate buttons:
b) Eight polycarbonate buttons at
bottom row
Figure 4.4.1 : Vision 2020i keypad
Button Description

USER User Control Changeable Settings.

Technician Control Changeable

TECHNICIAN
Settings.
The top right Authorization button is
for password log in to gain authorization,
FACTORY Factory Control Changeable Settings.
to the access setting menu.
The top left six operator buttons Unit information / Compressor
MENU
functions are to view status only, except Information.

the Setpoint button also allows setting

changes after gained authorization. ALARM RESET
Display the active alarms and to
perform alarm manual resets.

The three buttons at the bottom left are Scroll the various screens when the
to access different level of setting cursor is in the top left of the display.
If the cursor is inside a numeric field,
changes. UP the button increases or decreases
the corresponding value. If the field is
These are 'User', 'Technician' and a selection, pressing the button
displays the available options.
'Factory' levels, from left.
DOWN See the UP arrow
It can only be access depend on the
password level. The higher password can
To move the cursor around the
access the lower password level's setting ENTER screens and to save the values of the
set parameters
and not vice versa.

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4.0 ELECTRICAL

4.4.2 STATUS READING Press down arrow key or output key to

go to next screen:
4.4.2.1 Input status key
To read inputs status press input status
key:
The display is showing the data as
follows:

The display is showing the data as

follows: C1 Vapor Inj OFF
Hot Gas Bypass OFF
ANALOG INPUTS

Supply Temp 044.8 F [07.1C]

Return Temp 055.6 F [13.2C]
Suction Pres 073 PSI [05.2BAR]
Disch Press 179 PSI [12.9BAR]
Repeat the same steps to go to other
relay outputs screen:
Press down arrow key or input key to
go to next screen: 4.4.2.3 Compressor status key
To read compressor status press
compressor status key:

The display is showing the data as

follows:
The display is showing the data as
ANALOG INPUTS follows:

C1 Amps 101A COMPRESSOR 1 STATUS

C1 Disc T 125.2F [51.8C]
Comp 1 OK
Amps= 100A
FLA1= 230A
Capacity= 025.5%
Repeat the same steps to go to other Status=ON-LOAD
sensor inputs screen:
Press down arrow key or press
4.4.2.2 Output status key compressor key to go to next screen:
To read relay outputs status press
output status key:

The display is showing the data as

The display is showing the data as follows:
follows:
COMPRESSOR 1 HISTORY 1
RELAY OUTPUTS
Today Total
Comp 1 ON-LOAD Run Hour 05 0006
Alarm Status OFF Cycle 02 0006
Control Power ON
Last On 04/24 19:06
SDD Control OFF
Last Off 04/24 19:03
C1 Liquid Inj OFF
CW Pump ON

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4.0 ELECTRICAL

4.4.2.4 Setpoint key:

REAL TIME CLOCK
To read the setpoint value press
setpoint key Day > MONDAY
Time > 16:10
Date > 05/12/05

The display is showing the data as

follows: To set the date and time, you must be
authorized. See the authorization
SETPOINT 1 procedure and log in at least as user
level.
Supply Water Temp Press enter key to select the date or
Set point= 44.0 F [06.7C] time to alter and use the up-down arrow
Dead band= 0.8 F [0.5C] key to change the value and press enter
key to confirm.

To alter setpoint data, you must be

authorized. See the authorization
procedure and you must be authorized 4.4.2.6 Alarm history key:
at least as user level. To view the unit alarm history press
Press enter key to select the setpoint to alarm history key:
alter and use the up-down arrow key to
change the value and press enter key to
confirm.
The display is showing the data as
follows:

ALARM HISTORY
Press down arrow key or press
setpoint key to go to next screen: 001-C1 Starter
19:03 05/12/05
TR: 030.2 LWT: 64.3 [17.9]
DP: 191 [13.6]
SP: 076 [5.4]
Repeat the same steps to go to other
setpoints screen and perform setpoint Press down arrow key or press alarm
modification. key to go to next screen for other alarm
history:
4.4.2.5 Clock key:
To read the current day, time and date,
unit scheduling and ice-cel mode
scheduling (optional), press the clock To clear alarm history, press input key
key and authorization key together and then
press the alarm key again. Now the
display should be showing No alarm

The display is showing the data as

follows:
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4.0 ELECTRICAL

4.4.3 Authorization
Press down arrow key or user key to go
4.4.3.1 Authorization key to next screen for other setpoint:
To get authorization level, press
authorization key:

To alter setpoint data, press enter key to

The display is showing the current select the setpoint to alter and use the
access level as view only: up-down arrow key to change the value
and press enter key to confirm.
AUTHORIZATION

Please Enter your

Password
Repeat the above steps for others
PASSWORD= 0000 setpoints.
Status=View

Press enter key and use the up-down 4.4.5 TECHNICIAN KEY and MENU
arrow key to change the password
settings and press enter key to confirm.
4.4.5.1 Technician status key
This key is use to view and change the
compressor FLA setpoint, sensors
Now the authorization status change to calibration, manually control digital
different access level. inputs and outputs, manually control
compressor. In order to gain access to
4.4.4 Advanced user key and this button, you must be authorized and
log in at least as user level. See the
menu
authorization section about this
procedure.
4.4.4.1 User Key
User key is use to view and change the 4.4.5.2 Technician status key main
pressure, ampere safety limits and menu
liquid injection temperature setpoints, Press technician key to go to
unit of measurements. In order to gain technician setpoints main menu:
access to this button, you must be
authorized and log in at least as user
level.
The display is showing the data as
follows:
Press the user key and display is
showing the data as follows: Technician Setpoints
Main Menu
USER SETPOINT 1 Comp FLA Calibration
Sensor Calibration
High Pressure Safety Manual Control
Limits Compressor Control
Hold= 246PSI [17.0BAR] Sensors Override
Unload= 256PSI [17.7BAR]
Cutout= 270PSI [18.6BAR] Press enter key to move the cursor
to the sub-menu.
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The display is showing the data as Use up or down arrow key to move the
follows: cursor to the desired 'Sensor
Calibration',
Technician Setpoints
Main Menu
Comp FLA Calibration
Sensor Calibration The display is showing the data as
Manual Control follows:
Compressor Control
Sensors Override Sensor Offset 1
Suction Press
4.4.5.3 Compressor FLA Calibration: Current = 076PSI [5.4BAR]
To calibrate compressor FLA, press Average = 187PSI [8.6BAR]
down arrow key to go the sub-menu 24Hrs MAX = 200PSI [11.4BAR]
'Comp FLA Calibration', 24Hrs MIN = 074PSI [4.6BAR]
Calibration = 00PSI [0.0BAR]

Press enter key to move the cursor to

The display is showing the data as calibrate the desired sensor and use the
follows: up-down arrow key to change the value
and press enter key to confirm.
Technician Setpoint 1
Comp 1 FLA CALIBRATION
211x00.66+97.80
FLA = 237A Repeat the above steps for others
Capacity C1 = 000.0% sensors calibrations.
Min. Percent Cal = 25.0%
Max. Percent Cal = 00A
4.4.5.5 Manual Control:
Press enter key to move the cursor to A digital input sensor or relay output
calibrate the comp FLA and use the up- can be controlled manually with the
down arrow key to change the value keypad. Digital input sensor or relay
and press enter key to confirm. output can be turned on, off manually
and placed back to auto mode.
To place a digital input or relay output
in manual control, the operator must be
authorized at technician level or higher.
4.4.5.4 To perform Sensor Calibration:
Press technician key to go to technician Press technician key to go to technician
setpoints main menu and press enter setpoints main menu and press enter
key twice to move the cursor to the key three times to move the cursor to
sensor calibration sub-menu: the manual control sub-menu:

The display is showing the data as The display is showing the data as
follows: follows:

Technician Setpoints Technician Setpoints

Main Menu Main Menu
Comp FLA Calibration Comp FLA Calibration
Sensor Calibration Sensor Calibration
Manual Control Manual Control
Compressor Control Compressor Control
Sensors Override Sensors Override

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Use up or down arrow key to move the Press technician key to go to technician
cursor to the desired digital input or setpoints main menu and press enter
relay output, key four times to move the cursor to the
manual control sub-menu:

The display is showing the data as

follows: The display is showing the data as
follows:
Digital Inputs
Technician Setpoints
Manual Control
Main Menu
C1 Starter= Auto
Comp FLA Calibration
C1 Oil Lvl= Auto
Sensor Calibration
Unit Enable= Auto
Manual Control
Flow Switch= Auto
Compressor Control
Sensors Override
Press enter key to move the cursor to Use down arrow key to move the cursor
the desired point for manual control and to the desired compressor control
use the up or down arrow key to change screen, then press enter key to move the
the status of the digital input or relay cursor to compressor status position,
output to AUTO/CLOSE/OPEN or AUTO /MAN/OFF
AUTO/ON/OFF.

The display is showing the data as

The display is showing the data as follows:
follows:
Compressor Control
Relay Outputs Manual Override
Manual Control COMPRESSOR 1=AUTO
Alarm Relay Auto St= 0005
SDD Relay Auto Amps= 071.8
Liquid Inj C1 Auto Capacity= 025.0%
CW Pump Auto Status = OFF
Vap Inj Relay Auto
Use up or down arrow key to select
MAN and press enter key to confirm
Press enter key to confirm the change. the change. The compressor will start
or continue to run in hold state. Press
4.4.5.6 Compressor Control: the user key to continue hold, press the
Screw compressors can be controlled technician key to load and factory key
manually with the keypad. A to unload.
compressor can be turned on, off, or
placed in computer control. When a
compressor is controlled manually, it
can be commanded to load, hold, or Manual Hold Manual Load Manual Unload
unload. If safety limiting condition is If a safety condition is exceeded while
active, it will not accept a load operating manually, the compressor
command. will shutdown.
To place a compressor in manual CAUTION: Anti-recycle timer is
control, the operator must be authorized bypassed by manual control. DO NOT
and log in as technician level and start a compressor more than once
higher. every 15 minutes.
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NOTE: All compressors will revert

back to automatic control if the Sensors Manual
computer is the computer is not given a Override
load, unload, or hold command at least
once every 15 minutes. A command Supply Water Temp
can be repeated to meet the 15 minute Man Reading = 45.0 F [7.2C]
requirement for manual control. Manual Override = NO
To the change the settings of
compressor load/Unload, follow the
above steps and go to compressor Press enter key to move the cursor to
control. Use down arrow key to move the Man Reading and use the up or
the following and press to change the down arrow key to change the value of
settings. the analog reading, press enter key
move the cursor to the Manual
Load/Unload Control Override to enable, or disable the
manual override control.
Manual Pulse Settings
Pulse Rate= 001sec
Pulse Width= 001sec
Repeat the above steps for other sensors
override.

Caution: Sensors override require continuous

4.4.5.7 Sensors Override monitoring and observation by the field service
Value of analog readings can be personnel at all time during the unit operation.
temporary override during sensor Faulty sensor shall be replaced as soon as possible
failure. in order to allow the unit to be running in
To override the analog readings, the automatic mode.
operator must be authorized at
technician level or higher.
Press technician key to go to technician 4.4.6 Control Functions
setpoints main menu and press enter
key five times to move the cursor to the 4.4.6.1 Chilled Water Pump Interlock
Sensors Override sub-menu: And Flow Switch (CWP And
CWFS)
These are field installed switches, both
The display is showing the data as of which are used to ensure chilled
follows: water flow before the unit is allowed to
start. Failure of either one during
operation will cause the compressor to
Technician Setpoints
shut down.
Main Menu
Comp FLA Calibration A water flow alarm will be generated
Sensor Calibration and Rest Alarm must be pressed to
Manual Control clear the alarm.
Compressor Control
Sensors Override 4.4.6.2 Customer Control Interlock
Control contacts from an external
Use up or down arrow key to move the controller can be used to enable or
cursor to the desired analog reading, disable operation of the unit. The
wiring diagram specifies the terminals
to which the contacts must be wired. To
enable the unit, the contacts must be
The display is showing the data as closed. To disable the unit, the contacts
follows: must be opened.

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4.4.6.3 Anti-Recycle Timer that it loads at a predetermined rate.

The compressor motor requires an anti- This is a valuable tool, since it can help
recycle time delay which prevents reduce power consumption and demand
restart for 15 minutes after a start. The charges. Two variables are used to
purpose of this feature is to avoid define the ramp profile: Ramp rate and
frequent starts which tend to elevate the start point. Ramp rate defines the length
motor winding temperature and impose of time the unit takes to load from start
undue wear on contactors. The point to full load. Start point is the
controller will not restart the percent of full load at which the ramp
compressor motor until the 15 minutes begins. The ramp rate A setpoint can be
have elapsed. set anywhere from 0.1 to 1.0, smaller
values producing slower loading rates.
4.4.6.4 On Delay Timer The ramp start B setpoint can be set
A Compressor on delay timer of one or anywhere between 0 and 50%. The
two minutes is incorporated to prevent compressor will load quickly to this
two compressors from starting at the value and then follow the ramp slope
same time and ensures that the system from there. See Table 4.4.6.6 for ramp
load requires another compressor. The rates at various settings.
compressor output status will display
the timer count-down during this 4.4.6.7 Staging Control
timing. On multiple-compressor machines,
when the controller determines that a
4.4.6.5 Load Control compressor is fully loaded and
The controller controls the leaving temperature is not being maintained,
water temperature within a narrow another compressor is added. When
deadband by pulsing load and/ or unloading, a compressor is taken off
unload solenoids on the compressor. line when the computer determines that
The load and unload solenoids position the remaining compressors can control
the slide valve within the compressor to water temperature.
control its capacity. The controller
determines a desired level of loading 4.4.6.8 Modmotor Setback Control
and varies pulse duration depending on A computer contact and a resistor are
difference between load target and wired in parallel in the modmotor
actual load. The load target is varied control circuit. The contact is controller
based on rate of approach to desired controlled to open under light load
temperature preventing significant conditions. This lowers liquid level
temperature oscillations. The status of slightly, preventing excessive liquid
the compressor can be observed by level in the evaporator.
displaying the compressor control
point. 4.4.6.9 Sump Heater Control
Each compressor is fitted with an oil
4.4.6.6 Ramp Control sump band-heater. The heater is
Another feature of the controller is energized at all times when compressor
ramp control, which is the ability to is off and de-energized when the
vary load time of the machine from compressor is running.
start. Often when the machine is Its purpose is to prevent refrigerant
started, the water in the chilled water migration into the oil during shut down.
circuit is warm, and the unit will go to For this reason, it is essential that
full load quickly. With ramp control, heaters be energized for 24 hours
the user can program the computer so before starting a compressor.

TABLE 4.4.6.6 Ramp Rates for Several Setpoints (In Minutes)

Ramp 1 Comp. 2 Comp. 3 Comp 4 Comp
Rate Start Point Setpoint Start Point Setpoint Start Point Setpoint Start Point Setpoint
Setpoint
30% 50% 75% 30% 50% 75% 30% 50% 75% 30% 50% 75%
0.1 12.0 9.0 4.5 22.0 18.5 14.0 29.0 25.5 21.0 33.0 29.0 25.0
0.2 6.0 5.0 2.0 11.5 10.0 8.0 16.0 14.0 12.0 18.0 16.0 14.0
0.3 4.0 3.0 1.5 8.0 7.0 5.5 11.0 10.0 9.0 13.0 12.0 11.0
0.4 3.0 2.5 1.0 6.5 5.5 4.5 9.0 8.0 7.0 11.0 10.0 9.0

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4.4.6.10 Suction/ Discharge Pressure pressure alarm will be recorded by the

Differential Control controller. Reset by pressing the Reset
(SDD Control) Alarm button on the controller.
Standard setpoint is 270psig[18.6BAR].
This control function seeks to prevent a
low differential pressure alarm. It
monitors the difference between
4.4.6.14 Optical Oil Level Sensor (LS)
condenser and evaporator pressure. If An optical oil level sensor is located in
this difference is less than 25 psid each compressor. If low oil indication
[1.7BAR] for more than 10 seconds, (digital input is OFF) persists for 60
and evaporator pressure is above 39 seconds during compressor operation,
psig [2.7BAR], the controller will open the controller will then shut down the
a set of contacts in the modmotor compressor. The status of the oil level
circuit, causing valves to travel in the sensor can be seen on the computer
closed direction. This starves the display.
evaporator, which increases pressure Failure is indicated on the alarm pilot
difference. When this difference light. The low oil alarm will be
exceeds 25 psid [1.7BAR], modmotor recorded by the computer.
control returns to normal.
CAUTION: Do not start compressor 4.4.6.15 High Oil Temperature
manually more than once every 15 Thermostat (12TAS)
minutes. Verify that chilled water flow A thermostat is located in each
switch is closed. compressor which will open the
compressor run circuit if oil
4.4.6.11 Evaporator Freeze Shutoff temperature exceeds 203F [95C]. The
If the leaving chilled water temperature high oil temperature pilot light will
drops below the freeze setpoint, the indicate an excessive oil temperature
controller will shut down the unit and and a No-Run error will be recorded by
store the freeze alarm. After solving the the computer. Reset is activated by
problem, press Reset Alarm on the pressing the Reset Alarm button on
controller to clear the alarm. controller.

4.4.6.12 Low Pressure Cut-off 4.4.6.16 Overload Protector (M2OL)

This function protects the unit from A solid state overload protects each
operating at abnormally low evaporator compressor by three phase current
refrigerant pressure. The controller will monitoring to prevent high current
shut down the compressor when draw. The trip setting is factory set and
evaporator pressure falls below the low is reset by pressing button on overload
pressure setpoint and turn on the alarm after correcting problem. The Reset
pilot light. Alarm button on controller must also
A low pressure alarm will be recorded be pressed to clear the alarm. A no-run
by the controller. Reset by pressing the error is stored in the controller.
Reset Alarm button on the controller.
Standard setpoint is 28 psig [1.9BAR]. 4.4.6.17 Phase Control Relay (PCR)
The PCR protects the unit from the
4.4.6.13 High Pressure Cut-off following electric supply malfunctions:
This function protects the compressor Undervoltage, phase reversal and single
from operating at abnormally high phasing. If the PCR trips, a control
discharge refrigerant pressures. The relay (lCR) will de-energize and open
controller will shut down the the control circuit. A green LED
compressor when condenser pressure indicates presence of power supply.
reaches the high pressure set point, and The yellow LED indicates a good
turn on the alarm indicator lamp on the voltage supply. The power loss setpoint
control box. The high discharge is factory set to AUTO to allow

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automatic start after PCR failure. method of control is enhanced with adaptive, self-
Compressor will not start for 15 learning, fan control logic. The end result is
minutes after failure. To select manual condenser control that offers significantly reduced
reset, set power loss setpoint to fan cycling and improved efficiency. The two
MANUAL. In this case, a power loss types of air-cooled condenser control logic are
alarm will be stored by the controller explained as follows:
and Reset Alarm must be pressed to
start.
1. Adaptive Individual Air-cooled Condenser
Control
4.4.6.18 Sensor Alarm This type of control is based upon a single
If the computer measures an analog compressor per circuit. The individual
value (temperature, pressure.) that is far discharge pressure on that circuit will be the
beyond normal operating values, the controlling pressure.
associated compressors are shutdown.
The computer then stores the alarm 2. Adaptive Air Combined Air-cooled
code corresponding to the sensor alarm. Condenser Control
A sensor alarm indicates a problem in This type of control is based upon a condenser
the analog measurement system. that is controlled by the highest discharge
pressure from any one of the compressors
4.4.6.19 No-Stop Alarm sharing that circuit (compressor 1&2 - share;
compressor 3&4 - share). The highest
If the controller turns off a compressor,
discharge pressure between the sharing
but the compressor digital input does
not turn off, a No-Stop alarm is compressors will be the controlling pressure.
generated. The computer will turn off
the control power relay which disables
all compressor control circuits and will 4.5.1 Air Cooled Condenser
turn on the alarm light. This alarm Control Setpoints
indicates a wiring or hardware error.
The air-cooled condenser setpoints are as follows:

4.4.6.20 Low Differential Pressure Setpoint COND Stage 1 ON - Condenser stage 1

on.
Alarm
For proper lubrication, a compressor Setpoint COND Stage 2 OFF - Condenser stage 2
requires a 25 psid [1.7BAR] differential off.
pressure between condenser and Setpoint COND DIFF ON - Differential
evaporator pressures. If the differential pressure for
pressure is less than 25 psid [1.7BAR] additional
for 3 minutes while a compressor is condenser stages.
operating, all compressors will be shut
down. The controller will store the low Setpoint COND DIFF OFF - Differential
differential pressure alarm code and pressure for
turn on the alarm light. The Reset subtracting
Alarm key must be pressed to clear the condenser stages.
alarm. A compressor must be operating for the condenser
fans to operate. The condenser points (i.e. fans)
will turn on based upon the value in setpoint
COND Stage 1 ON. When the discharge pressure
4.5 CONDENSER FAN exceeds this value, the first condenser point is
CONTROL LOGIC turned on. If additional condenser points exist,
they will be turned on when the pressure exceeds
If the differential pressure is less, the controller the previous cut in value (COND Stage 1 ON for
provides two types of control logic for air-cooled the first stage) plus the value contained in COND
condensers. The type of control will be governed DIFF ON setpoint.
by the physical condenser layout of the unit. Each
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Condenser points (i.e. fans) will be turned off 4.5.3.1 Adaptive Control Logic
based upon the value in the setpoint COND ST2 The controller enhances the condenser
OFF (COND Stage 2 turn OFF point). As the control logic above with a unique,
discharge pressure is reduced, the condenser adaptive, self-learning fan control logic.
points will be turned off based upon the COND These enhancement results in a control
ST2 OFF setpoint, plus the value in the COND scheme that offers reduced fan cycling
DIFF OFF setpoint for each stage number above and improved efficiency. Adaptive
stage 2. Stage 2 of condenser staging will be Control Logic automatically adjusts the
fan cut-in offset based upon the
turned off based upon the value in the setpoint
following criteria:
(COND ST2 OFF). See below for an example of
condenser staging. 1. If the last fan turned on (including
FAN 1) is cycled off in 10 minutes
or less, then a COND ON OFFSET
4.5.2 Increasing Condenser value will be incremented by 5 psig
Pressure [0.3 BAR]. This increases the fan 1
turn on value (COND ST1 ON plus
(Example of 4 stage fan cycling) COND ON OFFSET) which in turn
COND FAN1 ON when discharge pressure is > increases all of the fan turn on
140psig [9.7BAR] (COND Stage 1 ON setpoint) settings. This process will continue
until fan cycling ceases or the
COND FAN2 ON when discharge pressure is > adjusted turn on point for the last fan
156psig [10.8BAR] (COND Stage 1 ON plus stage is 217 psig [15.0BAR]. This
1xCOND DIFF ON setpoint values) will also be a setpoint.
COND FAN3 ON when discharge pressure is > 2. The cut-in offset (COND ON
172psig [11.9BAR] (COND Stage 1 ON plus OFFSET) will be decreased by 5
2xCOND DIFF ON setpoint values) psig [0.3 BAR] if the last fan to be
turned on has not cycled off within 1
COND FAN4 ON when discharge pressure is > hour. The offset will continue to
188psig [13.0BAR] (COND Stage 1 ON plus decrease by 5 psig [0.3 BAR] every
3xCOND DIFF ON setpoint values) 10 minutes unless fan cycling begins
again.
And so on for the number of condenser fans
supplying the circuit. The Adaptive Control Logic will only
affect the condenser fan turn on logic, it
will not affect the fan turn off logic.
4.5.3 Decreasing Condenser
Pressure
(4 fan example "continued") 4.6 Master/Slave Control
Sequence
COND FAN4 OFF when discharge pressure is <
124psig [8.5BAR] (COND Stage 2 OFF plus The optional master/slave control sequence is
2xCOND DIFF OFF setpoint values) used to sequence multiple chillers in one
installation according to the building load
COND FAN3 OFF when discharge pressure is < demand. It also controls the dedicated chilled
118psig [8.1BAR] (COND Stage 2 OFF plus water pump or motorized valve.
1xCOND DIFF OFF setpoint values) Vision 2020i Controller offers this feature with
COND FAN2 OFF when discharge pressure is < minimized field wiring cost compare to
112psig [7.7BAR] (COND Stage 2 OFF setpoint conventional method that involves lots of
value) hardware cost. It is carried out this control
function via the advanced DBLAN
COND FAN1 OFF when discharge pressure is < communication bus to implement the network
105psig [7.2BAR] (COND Stage 1 OFF setpoint management for multiple chillers lead/lag
value) communication, sequencing and monitoring.
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4.6.1 Principle of Operation via DBLAN communication bus

Example: 6 chillers network with 4 units on duty and 2 units standby

Graphic
Display
(option)

DBLAN

DB3 DBG1 DB3 DBG1 DB3 DBG1 DB3 DBG1 DB3 DBG1 DB3 DBG1

DB1 DB1 DB1 DB1 DB1 DB1

DB1 DB1 DB1 DB1 DB1 DB1

#1 #2 #3 #4 #5 #6

Notes
a) Each chiller has a stand-alone master DB3 board and dedicated graphic display with multiple DB1
expanders board connected to J23 on DB3
b) Each chiller DB3 will be connected to DBLAN network through J11 connector
c) The chiller lead/lag selection can be determined by
Manual lead/lag setpoint
Schedule and holiday setup
Alarm conditions
d) The lead/lag selection determine the chiller operation sequence as follows,
Lead chiller Normal chillers operation sequence When DBLAN fails
selection

1 1, 2 & 3 on duty, 4, 5 & 6 standby 1, 2 & 3 on duty

2 2, 3 & 4 on duty, 5, 6 & 1 standby 2, 3 & 4 on duty

3 3, 4 & 5 on duty, 6, 1 & 2 standby 3, 4 & 5 on duty

4 4, 5 & 6 on duty, 1, 2 & 3 standby 4, 5 & 6 on duty

5 5, 6 & 1 on duty, 2, 3 & 4 standby 5, 6 & 1 on duty

6 6, 1 & 2 on duty, 3, 4 & 5 standby 6, 1 & 2 on duty

e) If the lead/lag selection is changed over to a different chiller, the sequence of operation will be
rotated
f) Each chiller will use a network address setpoint to determine individual chiller network address
g) Each chiller will require a dedicated chilled water pump or motorized valve digital output, unit
enable and chilled flow status digital inputs as well as enable next output command.

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4.6.2 Sequence Of Operation

a) LWT (LWT Setpoint + Enable Next
1. When the customer enable input is on to deadband)
start the lead unit, the chilled water pump
starter or motorized valve control point will b) After a enable next time delay of 3
close and water will start to flow through the minutes (adjustable) and
evaporator, this will activate the flow switch. c) When the lead units packaged capacity is
The flow switch and water pump status are higher than Next on setpoint,
interlocked and feedback as digital input to
for example, WCFX2, %FLCP C1 & %FLCP C2
the chiller and upon receipt of a valid 'on'
Next on setpoint
signal, the lead chiller will begin to execute
its running program. or it is being lockout by an alarm.
2. The controller will start and load the
compressor(s), upon achieving full load; it
will send an output signal via the DBLAN to
enable second unit (lag 1) 4.7 VISION 2020i LOCAL
3. The second unit will now command its chilled
AREA NETWORK
water pump to start if the customer unit (DBLAN)
enable is activated. The second chiller will
start and load the compressor(s) until it A DBLAN network is made up of several
reaches full load chillers controller. Each units controller can be
programmed and connected to the local DBLAN
4. When the second chiller or lag 1 unit reaches network that allows multiple units sequencing
full load, it will enable the third chiller. control without additional hardware.
5. The chiller will keep cascading until all
Every DBLAN node must be addressed to be
chillers on duty are at full load.
identified by the other nodes. Each address (an
6. If the leaving water temperature falls below integer number) must be unique in the network
setpoint, all of the chillers will begin to for avoiding messages mismatch: in case two or
unload evenly. more nodes have the same identifying address the
7. If the load drops below 45% total capacity, network cannot work.
delay the last unit (lag 3) will be disabled, and The max address number selectable is in the 1-16
the remaining three units will load up to for the Vision 2020i controller boards and 17-32
compensate if necessary. The pump for chiller range for the Vision 2020i User terminal.
4 will be shut off.
8. As the load demand falls, the lag 2 unit will The three chiller unit combinations:
be disabled below 45% total capacity, and so Controller with address of 1 connect to Terminal
on until the load falls enough to shut off the with address of 17
lead chiller.
Controller with address of 2 connect to Terminal
9. Each unit in the network can monitor the with address of 18
operation of other units via DBLAN. If the
master unit is having critical alarm, the lag 1 Controller with address of 3 connect to Terminal
will take over as the master unit with address of 19
automatically.
Follow the following steps:
10. In order to enable next unit, the following
conditions must met

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4.8 NETWORK CONNECTION DIAGRAM

Adr:17 Adr:18 Adr:19
Vision 2020i Vision 2020i Vision 2020i
Terminal Terminal Terminal

Telephone Cable Telephone Cable Telephone Cable

J10 Adr:1 J10 Adr:2 J10 Adr:3

Vision 2020i Vision 2020i Vision 2020i
Controller Controller Controller

J11 J11 J11

RS 485 Cable RS 485 Cable

max 500 meters max 500 meters

The 6 core telephone cables (to J10 socket) are supply by the manufacturer.
The 3 core RS 485 data cables (to J11 socket) are supply by the customer.
Pay attention to the network polarity:
RX+/TX+ on one controller must be connected to RX+/TX+ on the other controller; the same is true for
RX-/TX- and GND.

4.9 HARDWARE SETTINGS Change the display address setting to 0 as follow.

4.9.1 Addressing the Vision Display address

2020i controller Setting : 0
At the Vision 2020i terminal, push
simultaneously the last three keys on the lower
right corner of the Vision 2020i terminal
keyboard. Push them for at least 5 seconds.

Vision 2020i
5 sec
Turn off DB3 controller.

At the Vision 2020i DBG1 terminal, hold

simultaneously the Alarm key and Up arrow
key, turn on DB3 controller and hold these keys
This display will appear: until Self Test mask is appeared.
Display address
Setting : 17 Vision 2020i

I/O Board address: 01

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controller address (for first chiller, it is 01) that

*********************************** you want to configure. Once you select the
SELF TEST
PLEASE WAIT address then press enter button
************************************
The display will appears:

Terminal config
Press ENTER
To continue
The following mask will appear. Set pLAN
address to 1 (or accordingly) using Up and
Down arrow key. Press Enter key to save and
exit.
PLAN Address : 1
Up : Increase Push enter to continue.
Down : Decrease Then the display appears:
Enter : Save & Exit
P:01 Adr Priv/Shared
Trm1 17 Pr
Trm2 32 Sh
Trm 3 None --- OK? NO

The terminal display will become blank after

Enter key is pressed. Please proceed to next
section on Addressing the Vision 2020i DBG1
Terminal. Set Trm1, Trm2 and Trm3 to 17 Pr,32 Sh
and None ---, change the 'NO' to 'YES'(to
confirm and save) and press enter.
4.9.2 Addressing the Vision Note: Pr = Private, Sh = Share.
2020i DBG1 terminal For multiple units with master-slave sequencing
At the Vision 2020i DBG1 terminal, hold control features, at the second chiller unit Vision
simultaneously the last three keys on the lower 2020i terminal; repeat step 1 by holding the three
right corner of the Vision 2020i terminal keys again. The display will appears:
keyboard. Hold them for at least 5 seconds.
Display address
Vision 2020i Setting : 18
5 sec
I/o Board address: 02

The display will appears:

The address display (18) is the correct setup for
the second chiller unit with the controller address
Display address
of two (P:02).Press enter to confirm the settings
Setting : 17
and the display will appears:
I/o Board address: 01
Terminal config
Press ENTER
To continue

The first line is the address of the terminal display

that you are using, (for first chiller, it is 17). The
next line allows you to select the Vision 2020i
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Set Trm1, Trm2 and Trm3 to 18 Pr,32 Sh Set Trm1, Trm2 and Trm3 to 19 Pr,32 Sh
and None ---, change the 'NO' to 'YES'(to and None ---, change the 'NO' to 'YES'(to
confirm and save) and press enter. confirm and save) and press enter.
P:02 Adr Priv/Shared P:02 Adr Priv/Shared
Trm1 18 Pr Trm1 19 Pr
Trm2 32 Sh Trm2 32 Sh
Trm 3 None --- OK? NO Trm 3 None --- OK? NO

At the third chiller unit Vision 2020i terminal: With the above settings, terminal with address 17
Press the three keys again, the display will will only work with the controller with address 1,
appears: terminal 18 will only work with the controller
Display address with address 2, terminal 19 will only work with
Setting : 19 the controller with address 3 and a terminal with
address 32 will work with both.
I/o Board address: 03

4.9.3 Vision 2020i Controller

LED Status
The address display (19) is the correct setup for
the third chiller unit with the controller address of Vision 2020i controller have three LEDs between
three(P:03).Press enter to confirm the setting the J3 and J4 connectors for indicating basic node
and the display will appears: status. They are Red, Yellow and Green coloured.

Terminal config
Press ENTER
To continue Red Yellow Green

At the start-up all LEDs are ON and after few

seconds OFF again. After 5 15 seconds elapse,
then LED configuration is among those listed
below.

Table 4.9.3 LED Status

LED STATUS DESCRIPTION

Vision 2020i controller is synchronized with all the other DBLAN nodes.
ON
The node is working correctly.
GREEN
OFF Vision 2020i controller is not network connected or it doesnt receive any signal from the DBLAN

BLINKING Vision 2020i controller is transmitting data to other network nodes.

YELLOW
OFF Vision 2020i controller is not transmitting messages.

OFF No hardware and software problem.

Vision 2020i controller software not compatible or variables database not correct, contact Dunham-
ON
RED Bush Service Personnel.

Vision 2020i hardware is not compatible - Ram is smaller than 32 KB.

BLINKING
The Vision 2020i controller is just for working in stand-alone mode.

AFHX Standard R134a 60Hz IOM Manual

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5.0 MAINTENANCE

5.1 GENERAL heat transfer surfaces can be detected by

recording full load performance data on
As with all mechanical equipment, a program of the log sheet. The best measure of
regular inspection, cleaning and preventive performance of evaporator is approach,
maintenance by trained personnel will contribute which is the difference between leaving
greatly to the long satisfactory service life of this water temperature and saturated
product. refrigerant temperature at the pressure in
the vessel. At full load, read evaporator
pressure and leaving chilled water
5.2 PERIODIC INSPECTION temperature on the computer. Then use
Table 5.4.2 to find saturated temperature
Read essential temperatures and pressures in evaporator. Then calculate approaches
periodically to see that they indicate normal as follows:
operation. It is a good idea to record these
Evaporator Approach = T lvg chilled
readings on a log sheet. If any abnormal operation
water - T sat evaporator
is observed, try to remedy it. See Trouble
Shooting Guide Section. If the approach increases by more than
2F [1.1C] above the approach recorded
at clean conditions, the tubes should be
cleaned. It is generally advisable to clean
5.3 MONTHLY INSPECTION the waterside surfaces at least annually
Remote dirt and debris from condenser coil. Shut and more often if severely foul water is
unit down, open main disconnect, inspect control used. In chemical cleaning, a caustic
panel, checking for loose wires, burned contacts, solution is pumped through the heat
signs of overheated wires, etc. Restart unit and exchanger, which attacks dirt, slime and
check performance of controls. Check sight mineral deposits and flushes then away.
glasses for proper refrigerant charge, see Chemicals can be recommended by water
charging. treatment specialists, but it is important to
rinse the system thoroughly after cleaning
to remove the chemicals before they
attack the metal surfaces.
5.4 VESSEL MAINTENANCE
5.4.1 GENERAL
The efficient performance of the
5.5 AIR COOLED
evaporator and condenser heat transfer CONDENSER CLEANING
surfaces is essential for efficient The face of the condenser should be cleaned at
performance of your packaged water
least once month during operation. If conditions
cooling machine. If these surfaces
accumulate a film of dirt, scale or slime, are bad and condensers pick up dirt very quickly,
their performance efficiency will degrade it is suggested that they can be cleaned more
substantially. The refrigerant side of heat frequently. If the condenser is allowed to get too
transfer surfaces does not foul since dirty, the unit will run at high head pressure and
refrigerant is a good solvent and it is in a will not give satisfactory performance.
closed, filtered cycle. Waterside surfaces
can foul from the water system. A Dirty coils can be cleaned using a soft brush or by
program of water treatment can slow the flushing with cool water or commercially
rate of fouling on heat transfer surfaces, available coil cleaners. DO NOT USE HOT
but not eliminate it. WATER OR STEAM. To do so will cause
excessive pressure in the system. The face of the
5.4.2 WATER SIDE CLEANING OF condenser should be cleaned at the beginning of
EVAPORATOR the season and periodically thereafter if
conditions require.
The effects of fouling of the evaporator
AFHX Standard R134a 60Hz IOM Manual
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5.0 MAINTENANCE

TABLE 5.4.2 R134a PRESSURE/ TEMPERATURE PROPERTIES

PRESS TEMP. PRESS TEMP. PRESS TEMP. PRESS TEMP. PRESS TEMP.

PSIG KPA F C PSIG KPA F C PSIG KPA F C PSIG KPA F C PSIG KPA F C

0.00 101.38 -14.70 -25.94 53.00 466.90 56.90 13.83 106.00 832.41 90.90 32.72 159.00 1197.93 115.00 46.11 212.00 1563.45 134.10 56.72
1.00 108.28 -12.00 -24.44 54.00 473.79 57.70 14.28 107.00 839.31 91.50 33.06 160.00 1204.83 115.40 46.33 213.00 1570.34 134.40 56.89
2.00 115.17 -9.50 -23.06 55.00 480.69 58.50 14.72 108.00 846.21 92.00 33.33 161.00 1211.72 115.80 46.56 214.00 1577.24 134.70 57.06
3.00 122.07 -7.10 -21.72 56.00 487.59 59.30 15.17 109.00 853.10 92.50 33.61 162.00 1218.62 116.20 46.78 215.00 1584.14 135.10 57.28
4.00 128.97 -4.80 -20.44 57.00 494.48 60.10 15.61 110.00 860.00 93.00 33.89 163.00 1225.52 116.60 47.00 216.00 1591.03 135.40 57.44
5.00 135.86 -2.60 -19.22 58.00 501.38 60.90 16.06 111.00 866.90 93.50 34.17 164.00 1232.41 117.00 47.22 217.00 1597.93 135.70 57.61
6.00 142.76 -0.50 -18.06 59.00 508.28 61.60 16.44 112.00 873.79 94.00 34.44 165.00 1239.31 117.40 47.44 218.00 1604.83 136.00 57.78
7.00 149.66 1.50 -16.94 60.00 515.17 62.40 16.89 113.00 880.69 94.50 34.72 166.00 1246.21 117.70 47.61 219.00 1611.72 136.40 58.00
8.00 156.55 3.50 -15.83 61.00 522.07 63.10 17.28 114.00 887.59 95.00 35.00 167.00 1253.10 118.10 47.83 220.00 1618.62 136.70 58.17
9.00 163.45 5.30 -14.83 62.00 528.97 63.90 17.72 115.00 894.48 95.50 35.28 168.00 1260.00 118.50 48.06 221.00 1625.52 137.00 58.33
10.00 170.34 7.20 -13.78 63.00 535.86 64.60 18.11 116.00 901.38 96.00 35.56 169.00 1266.90 118.90 48.28 222.00 1632.41 137.30 58.50
11.00 177.24 8.90 -12.83 64.00 542.76 65.30 18.50 117.00 908.28 96.50 35.83 170.00 1273.79 119.30 48.50 223.00 1639.31 137.60 58.67
12.00 184.14 10.60 -11.89 65.00 549.66 66.00 18.89 118.00 915.17 97.00 36.11 171.00 1280.69 119.70 48.72 224.00 1646.21 138.00 58.89
13.00 191.03 12.30 -10.94 66.00 556.55 66.80 19.33 119.00 922.07 97.50 36.39 172.00 1287.59 120.00 48.89 225.00 1653.10 138.30 59.06
14.00 197.93 13.90 -10.06 67.00 563.45 67.50 19.72 120.00 928.97 98.00 36.67 173.00 1294.48 120.40 49.11 226.00 1660.00 138.60 59.22
15.00 204.83 15.50 -9.17 68.00 570.34 68.20 20.11 121.00 935.86 98.40 36.89 174.00 1301.38 120.80 49.33 227.00 1666.90 138.90 59.39
16.00 211.72 17.00 -8.33 69.00 577.24 68.90 20.50 122.00 942.76 98.90 37.17 175.00 1308.28 121.20 49.56 228.00 1673.79 139.20 59.56
17.00 218.62 17.50 -8.06 70.00 584.14 69.50 20.83 123.00 949.66 99.40 37.44 176.00 1315.17 121.50 49.72 229.00 1680.69 139.50 59.72
18.00 225.52 20.00 -6.67 71.00 591.03 70.20 21.22 124.00 956.55 99.90 37.72 177.00 1322.07 121.90 49.94 230.00 1687.59 139.80 59.89
19.00 232.41 21.40 -5.89 72.00 597.93 70.90 21.61 125.00 963.45 100.30 37.94 178.00 1328.97 122.30 50.17 231.00 1694.48 140.10 60.06
20.00 239.31 22.80 -5.11 73.00 604.83 71.60 22.00 126.00 970.34 100.80 38.22 179.00 1335.86 122.60 50.33 232.00 1701.38 140.40 60.22
21.00 246.21 24.10 -4.39 74.00 611.72 72.20 22.33 127.00 977.24 101.30 38.50 180.00 1342.76 123.00 50.56 233.00 1708.28 140.80 60.44
22.00 253.10 25.40 -3.67 75.00 618.62 72.90 22.72 128.00 984.14 101.70 38.72 181.00 1349.66 123.40 50.78 234.00 1715.17 141.10 60.61
23.00 260.00 26.70 -2.94 76.00 625.52 73.50 23.06 129.00 991.03 102.20 39.00 182.00 1356.55 123.70 50.94 235.00 1722.07 141.40 60.78
24.00 266.90 28.00 -2.22 77.00 632.41 74.20 23.44 130.00 997.93 102.70 39.28 183.00 1363.45 124.10 51.17 236.00 1728.97 141.70 60.94
25.00 273.79 29.20 -1.56 78.00 639.31 74.80 23.78 131.00 1004.83 103.10 39.50 184.00 1370.34 124.50 51.39 237.00 1735.86 142.00 61.11
26.00 280.69 30.50 -0.83 79.00 646.21 75.50 24.17 132.00 1011.72 103.60 39.78 185.00 1377.24 124.80 51.56 238.00 1742.76 142.30 61.28
27.00 287.59 31.70 -0.17 80.00 653.10 76.10 24.50 133.00 1018.62 104.00 40.00 186.00 1384.14 125.20 51.78 239.00 1749.66 142.60 61.44
28.00 294.48 32.80 0.44 81.00 660.00 76.70 24.83 134.00 1025.52 104.50 40.28 187.00 1391.03 125.50 51.94 240.00 1756.55 142.90 61.61
29.00 301.38 34.00 1.11 82.00 666.90 77.30 25.17 135.00 1032.41 104.90 40.50 188.00 1397.93 125.90 52.17 241.00 1763.45 143.20 61.78
30.00 308.28 35.10 1.72 83.00 673.79 78.00 25.56 136.00 1039.31 105.30 40.72 189.00 1404.83 126.30 52.39 242.00 1770.34 143.50 61.94
31.00 315.17 36.20 2.33 84.00 680.69 78.60 25.89 137.00 1046.21 105.80 41.00 190.00 1411.72 126.60 52.56 243.00 1777.24 143.80 62.11
32.00 322.07 37.30 2.94 85.00 687.59 79.20 26.22 138.00 1053.10 106.20 41.22 191.00 1418.62 127.00 52.78 244.00 1784.14 144.10 62.28
33.00 328.97 38.40 3.56 86.00 694.48 79.80 26.56 139.00 1060.00 106.70 41.50 192.00 1425.52 127.30 52.94 245.00 1791.03 144.40 62.44
34.00 335.86 39.50 4.17 87.00 701.38 80.40 26.89 140.00 1066.90 107.10 41.72 193.00 1432.41 127.70 53.17 246.00 1797.93 144.70 62.61
35.00 342.76 40.50 4.72 88.00 708.28 81.00 27.22 141.00 1073.79 107.50 41.94 194.00 1439.31 128.00 53.33 247.00 1804.83 145.00 62.78
36.00 349.66 41.50 5.28 89.00 715.17 81.50 27.50 142.00 1080.69 108.00 42.22 195.00 1446.21 128.40 53.56 248.00 1811.72 145.30 62.94
37.00 356.55 42.50 5.83 90.00 722.07 82.10 27.83 143.00 1087.59 108.40 42.44 196.00 1453.10 128.70 53.72 249.00 1818.62 145.60 63.11
38.00 363.45 43.50 6.39 91.00 728.97 82.70 28.17 144.00 1094.48 108.80 42.67 197.00 1460.00 129.10 53.94 250.00 1825.52 145.90 63.28
39.00 370.34 44.50 6.94 92.00 735.86 83.30 28.50 145.00 1101.38 109.20 42.89 198.00 1466.90 129.40 54.11 251.00 1832.41 145.20 62.89
40.00 377.24 45.50 7.50 93.00 742.76 83.90 28.83 146.00 1108.28 109.70 43.17 199.00 1473.79 129.70 54.28 252.00 1839.31 146.40 63.56
41.00 384.14 46.40 8.00 94.00 749.66 84.40 29.11 147.00 1115.17 110.10 43.39 200.00 1480.69 130.10 54.50 253.00 1846.21 146.70 63.72
42.00 391.03 47.40 8.56 95.00 756.55 85.00 29.44 148.00 1122.07 110.50 43.61 201.00 1487.59 130.40 54.67 254.00 1853.10 147.00 63.89
43.00 397.93 48.30 9.06 96.00 763.45 85.60 29.78 149.00 1128.97 110.90 43.83 202.00 1494.48 130.80 54.89 255.00 1860.00 147.30 64.06
44.00 404.83 49.20 9.56 97.00 770.34 86.10 30.06 150.00 1135.86 111.30 44.06 203.00 1501.38 131.10 55.06 256.00 1866.90 147.60 64.22
45.00 411.72 50.10 10.06 98.00 777.24 86.70 30.39 151.00 1142.76 111.80 44.33 204.00 1508.28 131.40 55.22 257.00 1873.79 147.90 64.39
46.00 418.62 51.00 10.56 99.00 784.14 87.20 30.67 152.00 1149.66 112.20 44.56 205.00 1515.17 131.80 55.44 258.00 1880.69 148.20 64.56
47.00 425.52 51.90 11.06 100.00 791.03 87.80 31.00 153.00 1156.55 112.60 44.78 206.00 1522.07 132.10 55.61 259.00 1887.59 148.50 64.72
48.00 432.41 52.70 11.50 101.00 797.93 88.30 31.28 154.00 1163.45 113.00 45.00 207.00 1528.97 132.40 55.78 260.00 1894.48 148.70 64.83
49.00 439.31 53.60 12.00 102.00 804.83 88.80 31.56 155.00 1170.34 113.40 45.22 208.00 1535.86 132.80 56.00 261.00 1901.38 149.00 65.00
50.00 446.21 54.40 12.44 103.00 811.72 89.40 31.89 156.00 1177.24 113.80 45.44 209.00 1542.76 133.10 56.17 262.00 1908.28 149.30 65.17
51.00 453.10 55.30 12.94 104.00 818.62 89.90 32.17 157.00 1184.14 114.20 45.67 210.00 1549.66 133.40 56.33 263.00 1915.17 149.60 65.33
52.00 460.00 56.10 13.39 105.00 825.52 90.40 32.44 158.00 1191.03 114.60 45.89 211.00 1556.55 133.80 56.56 264.00 1922.07 149.90 65.50

NOTE : PRESSURE AND TEMPERATURE ARE STATED IN PSIA(KPA) AND F(C) RESPECTIVELY.

AFHX Standard R134a 60Hz IOM Manual

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5.0 MAINTENANCE

5.6 ELECTRICAL any operating condition, the circuit is short

MALFUNCTION of charge.

The unit has four devices designed to protect Be careful not to overcharge the machine.
compressor motors and manual motor controllers overcharging will result in considerable
from electrical malfunctions: Circuit breakers, liquid logging in the condenser, and
starter overload relays, under voltage relay, and excessive condensing pressure.
motor over temperature protectors (optional).
To add refrigerant, connect a refrigerant
If the under voltage relay trips, it is a sign of vessel to the 1/4" back seating port of the
trouble in incoming power. If it trips again after suction valve. Purge the air from the tube
resetting, call your electric utility to investigate with refrigerant gas before connecting.
the problem. If circuit breaker or motor overload With the unit running, open the refrigerant
relay or motor over temperature protectors trip, vessel vapor connection slightly. If the
this is a sign of possible motor trouble. DO NOT refrigerant vessel is warmer than the
reset and try to run compressor again. Call evaporator, refrigerant will more readily
authorized service representative to check for flow from the vessel into the unit.
motor trouble. Resetting these safety devices and
repeated starting could turn a minor motor
problem into a costly major motor burnout.
5.8 OIL CHARGE

The proper oil charge is in the unit as supplied

5.7 REFRIGERANT CHARGE
from the factory. Any operating compressor
should show oil return and oil overflow at all
5.7.1 GENERAL
time. If for some reason, a compressor runs low
All packaged chiller units are given a on oil, a low oil level switch in the compressor
complete charge of refrigerant at the will shut it down before any damage is done. In
factory. The type and amount of the event of a low oil shutdown, call a D/B
refrigerant required is in Physical authorized service agent to correct the problem.
Specifications. The total refrigerant shown DO NOT ADD OIL TO THE SYSTEM.
is for the entire system. Since these units
Note: Only DB 18 oil may be used in this
have separate circuits, each circuit should
package. Use of other oil is not
be considered separately for charging.
approved by Dunham-Bush, and will
In order to check proper refrigerant charge, result in poor performance of the
look in each liquid line sight glass with the
package. It is recommended to
aid of a flashlight during system operation.
change oil annually to prolong
At all operating conditions, the sight glass
the compressor life-time.
should be clear. If bubbles are visible at

AFHX Standard R134a 60Hz IOM Manual

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5.0 MAINTENANCE

5.9 TROUBLESHOOTING
SYMPTOM POSSIBLE CAUSE REMEDY

1. Unit will not a.) Power off. a.) Check main disconnect switch and main line fuses.
start. b.) No control power. b.) Check control transformer fusing.
c.) Compressor circuit c.) Close circuit breakers. If trip, check compressor.
breakers open.
d.) Phase control relay open. d.) Check for power supply problems ( low voltage, phase
imbalance). When corrected, press reset button.
e.) Flow Switch open. e.) Start pumps, check flow switch.
f.) Compressor switch open. f.) Turn switch on. Check alarm status. Correct problem.
g.) Controller shutdown not g.) Press reset button.
reset.
2. Compressor a.) Low voltage. a.) Check at main entrance and at unit. Consult power
hums but does company if voltage is low and increase wire size to the
not start. unit if voltage is normal at main and low at unit.
Voltage must be within 10% of motor nameplate
rating.
b.) No power on one phase of b.) Check fuses and wiring.
3 phase unit.
c.) Faulty starter or contactor. c.) Check the contacts and time delay on part wind start.
3. Compressor will a.) Cooling not required. a.) Apply load.
not start when b.) Computer's time delay b.) Wait 15 minutes max.
reset button is active.
pushed. c.) Phase control relay open. c.) See 1.( d.) above.
d.) Flow switch open. d.) See 1.( e.) above.
Check light: e.) Compressor switch open. e.) See 1.( f.) above.
None f.) Burned out signal light. f.) Check signal light bulbs.
i.) Wiring problem i.) Check wiring against drawing.
4. Compressor a.) Compressor drawing high a.) Check motor megohms. Reset overloads; run
overload. amps. compressor an check amps. Do not exceed RL x 1.25.
Call D/B serviceman.
5. High motor a.) Motor windings failing. a.) Check megohms. Reset by turning compressor switch
temperature off and then on.
6. Low suction a.) Inadequate feed to a.) Check to see that main expansion valve superheat.
evaporator.
b.) Inadequate refrigerant b.) See information on charging in Section 5.7.
charge.
c.) Fouling of waterside of c.) At high load, check evaporator approach (See Section
evaporator. 5.4). If approach is more than 2F [1.1C] above clean
valve, fouling is probably the trouble. Clean tube.
d.) Inadequate chilled water d.) Measure pressure drop across vessel and determine
flow. flowrate from Figure 3.3. If flow rate is low, check
chilled water pump, valves and strainers.
e.) Too much oil in system. e.) If all oil level sight glasses are full at all times, remove
oil until oil level shows at top of glass on a
compressor.
7. High discharge a.) Inadequate air flow across a.) Check condenser fan operation and condenser coil for
pressure. condenser clogging.
8. Oil low in sump. a.) Low oil level in a.) Low oil level in compressor sight glass is acceptable.
compressor.
9. Low oil a.) Low oil in compressor. a.) See Section 5.8.
shutdown.
10. Freeze warning. a.) Operating setpoint too low. a.) Check leaving water setpoint on controller.
b.) Load changing too rapidly. b.) Load on package must drop at reasonable rate for
automatic control to work properly.
11. Improper a.) Ramp rate incorrect. a.) See Section 4.4.6.5.
capacity control.

AFHX Standard R134a 60Hz IOM Manual

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5.0 MAINTENANCE

5.10 SAMPLE LOG SHEET SHEET NO............................

DUNHAM-BUSH SCREW COMPRESSOR PACKAGED CHILLER

NAMEPLATE DATA:
UNIT MODEL NO. ........................................................ UNIT NO. ....................................VOLTS: ............................ Hz ..................

UNIT SERIAL NO. ........................................................ COMPRESSOR MODEL NOS. ....................................................................

START UP : DATE .......................................... TIME....................................................

DATE

TIME

ELAPSED TIME METERS

COMP. NO.
1.
2.
SUCTION PRESSURE
3.
4.
1.
2.
DISCHARGE PRESSURE
3.
4.
1.
2.
DISCHARGE TEMPERATURE
3.
4.
1.

DISCHARGE SUPERHEAT 2.
(DISC. TEMP.-SAT. DISCH.)* 3.
4.
1.

DISCHARGE SUPERHEAT 2.
(DISC. TEMP.-SAT. SUCT.)* 3.
4.

EVAPORATOR WATER TEMPERATURE-IN

EVAPORATOR WATER TEMPERATURE-OUT

EVAPORATOR PRESSURE DROP

FTWG [KPA]

EVAPORATOR WATER FLOW GPM[M/HR]

CONDENSER AIR TEMPERATURE-IN

(AMBIENT) AC ONLY

1.

ACTUAL VOLTAGE 2.
COMPRESSOR AMPS 3.
4.

FAN AMPS

VOLTS

*USE TABLE 5.4.2 FOR OBTAINING SATURATED TEMPERATURE

THIS LOG SHEET IS PROVIDED AS A RECOMMENDATION OF THE READINGS THAT SHOULD BE TAKEN ON A PERIODIC BASIS. THE
ACTUAL READINGS TAKEN AND THE FREQUENCY WILL DEPEND UPON THE UNITS APPLICATION, HOURS OF USE, ETC. THIS TYPE OF
INFORMATION CAN PROVE VERY USEFUL IN PREVENTING AND/ OR SOLVING PROBLEMS THAT MIGHT OCCUR DURING THE LIFE OF
THE UNIT.

AFHX Standard R134a 60Hz IOM Manual

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Products that perform...By people who care

Manufacturer reserves the right to change specifications without prior notice.

Corporate Head Office

DUNHAM-BUSH HOLDING BHD
(Formerly known as Dunham-Bush (Malaysia) Bhd) (129358-X)

Lot 5755-6, Kidamai Industrial Park, Bukit Angkat

43000 Kajang, Selangor Darul Ehsan, Malaysia.
Tel: 603-8733 9898 Fax: 603-8739 5020
E-Mail: info@dunham-bush.com.my

www.dunham-bush.com