Rev 2.

0
DVM S Advance Service & Troubleshooting
Due to Samsung’s policy of ongoing product development, specifications are subject to change without prior notice.
Every effort has been made to insure that the information included in this presentation is as accurate as possible at
the time of it’s publication.

This presentation is provided as a guide to help HVAC field technicians understand the most common service and
diagnostic procedures for the Samsung DVMS VRF systems. This training module is not intended to replace
Samsung service manuals, technical data books, installation/operation manuals or other factory documents.

Only properly trained, HVAC professionals should attempt to install and service any Samsung heating and air-
conditioning system.

High Voltage Caution:

Extra care must be taken when working on or around DVM S equipment due to numerous high voltage components.
Whether installing or servicing DVM S equipment in the field or while attending Samsung HVAC training classes
which include powered simulators and equipment, be aware of the potential dangers of high voltage – use caution

This presentation may only be used with authorization by Samsung HVAC. Unauthorized use, duplication or
alteration of this presentation is prohibited.

For technical support issues, always contact your Samsung equipment provider.

www.samsunghvac.com www.schoox.com/login.php www.dvmdownload.com

2
Advance Service & Troubleshooting
TOPICS
 Basic System Operation

 Heat Pump Introduction

 Heat Recovery Introduction

 Indoor Unit (IDU) Control

 Outdoor Unit (ODU) Control

 Heat Pump Refrigerant Circuit
 Heat Recovery Refrigerant Circuit

3
 DVM S
Basic System Operation
Basic System Operation
Indoor Unit Control – On/Off
ODU Status

IDU Status RC Status

Refrigerant flowing Turn on

F3/F4 comm.
Thermo on
ON ON ON

Refrigerant stop Turn on

F3/F4 comm.
Thermo off
OFF ON ON

Refrigerant stop
F3/F4 comm. Turn off

OFF OFF OFF

5
Basic System Operation
Outdoor Unit Control – On/Off

OFF OFF OFF OFF

OFF

OFF OFF OFF ON

ON
 Any indoor unit in a “thermo on” condition will start the outdoor unit *Thermo on

OFF OFF OFF ON

OFF
 Example: IDU is ON but the EEV is closed (Thermo Off) – ODU is OFF *Thermo off

OFF ON OFF ON
ON
*Thermo on *Thermo off

6
Basic System Operation
Outdoor Unit Capacity Control

18,000 18,000 18,000 18,000

Btu/h Btu/h Btu/h Btu/h Outdoor unit
target capacity

OFF OFF OFF ON ON 18,000

*Thermo on Btu/h

18,000 18,000 18,000 18,000

Btu/h Btu/h Btu/h Btu/h

ON ON OFF ON ON 54,000
*Thermo on *Thermo on *Thermo on Btu/h

18,000 18,000 18,000 18,000

Btu/h Btu/h Btu/h Btu/h

ON ON OFF ON ON 18,000
*Thermo off *Thermo on *Thermo off Btu/h

7
Basic System Operation
Operating Temperature Range For Outdoor Unit Start
 When ambient temperature is out of range, the system will not start and generates error
 E440 – Prevention of heat operation
 E441 – Prevention of cool operation
 System checks ambient temperature condition only on outdoor unit (compressor) start up
 The DVM S outdoor units will operate when ambient temperatures are exceeded however capacity and
efficiency will decrease accordingly
-13°F 23°F

Cooling start Cooling operation area

prohibited
-5~48℃(23~120℉)
Outdoor
temperature
Heating operation area
Heating start
-20~24℃(-4~75 ℉) prohibited

75°F 86°F

8
 DVM S
VRF Heat Pump Introduction
Heat Pump Introduction
Heat Pump Outdoor Unit

OD Fan
Control Box
Control Box
OD Fans

OD Heat OD Heat
Exchanger Exchanger

4-WAY V/V
4-WAY V/V

Accumulator
Accumulator

Subcooler
Subcooler

Compressor Oil Separator

Gas V/V Compressor
Liquid V/V Oil Separator Gas V/V Liquid V/V

10
Heat Pump Introduction Name
INV Inverter Compressor
OFM Outdoor Fan Motor
Heat Pump Refrigerant Circuit – Single Fan 1 compressor unit OHX Outdoor Heat Exchanger
AC Accumulator
OS Oil Separator
SV_G IC Intercooler
OFM IPMC IPM Cooler
T_A
CH Crank Case Heater
T_CO
HPS High Pressure Sensor
OHX LPS Low Pressure Sensor
HPSW High Pressure Switch
E_M Main EEV
E_EV EVI EEV
V_4W T_S CV_E E_M V_ES EVI Sol. Valve

E
V_EB EVI Bypass Valve
HPS V_HG Hot Gas Bypass Valve
V_EB V_4W 4Way Valve
CV_D s T_EO
T_EI V_AR Accumulator Oil Return Valve
IC CV_E EEV Bypass Check Valve
E_EV

E
CV_D Discharge Check Valve
OS
T_D Discharge Temp. Sensor
HPSW
T_D
T_S Suction Temp. Sensor
T_CT IPMC T_CO Cond Out Temp. Sensor
V_HG AC
s

LPS T_EI EVI In Temp. Sensor

INV
T_EO EVI Out Temp. Sensor
CH T_L T_L Liquid Tube Temp. Sensor
SV_L T_CT Comp. Top Temp. Sensor
s V_AR T_A Ambient Temp. Sensor
V_ES
SV_G Gas Pipe Service Valve
SV_L Liquid Pipe Service Valve

12
Heat Pump Introduction Name
INV Inverter Compressor
Heat Pump Refrigerant Circuit – Dual Fan 1 compressor unit OFM Outdoor Fan Motor
OHX Outdoor Heat Exchanger
AC Accumulator
OS Oil Separator
SV_G
OFM OFM IC Intercooler
T_A
IPMC IPM Cooler
T_C CH Crank Case Heater
OHX O HPS High Pressure Sensor
LPS Low Pressure Sensor
HPSW High Pressure Switch
E_M Main EEV
V_4W T_S CV_E E_M E_EV EVI EEV

E
V_ES EVI Sol. Valve
HPS V_EB EVI Bypass Valve
V_EB V_HG Hot Gas Bypass Valve
CV_D s T_EO
T_EI V_4W 4Way Valve
IC V_AR Accumulator Oil Return Valve
E_EV

E
CV_E EEV Bypass Check Valve
OS
CV_D Discharge Check Valve
HPSW T_D Discharge Temp. Sensor
T_D V_HG
T_CT IPMC T_S Suction Temp. Sensor
AC T_CO Cond Out Temp. Sensor
s

LPS
INV
T_EI EVI In Temp. Sensor
CH T_L T_EO EVI Out Temp. Sensor
SV_L T_L Liquid Tube Temp. Sensor
sV_AR T_CT Comp. Top Temp. Sensor
V_ES T_A Ambient Temp. Sensor
SV_G Gas Pipe Service Valve
SV_L Liquid Pipe Service Valve

13
Heat Pump Introduction Name
INV Inverter Compressor
OFM Outdoor Fan Motor
Heat Pump Refrigerant Circuit – Dual Fan 2 compressor unit
OHX Outdoor Heat Exchanger
AC Accumulator
SV_G OS Oil Separator
OFM IC Intercooler
T_A
IPMC IPM Cooler
T_CO CH Crank Case Heater
OHX HPS High Pressure Sensor
LPS Low Pressure Sensor
HPSW High Pressure Switch
CV_E E_M E_M Main EEV

E
V_4W E_EV EVI EEV
T_S
V_ES EVI Sol. Valve
V_EB EVI Bypass Valve
HPS IPMC IPMC V_HG Hot Gas Bypass Valve
V_4W 4Way Valve
CV_D CV_D V_AR Accumulator Oil Return Valve
OS OS IC CV_E EEV Bypass Check Valve
V_EB T_EI
s T_EO CV_D Discharge Check Valve
E_EV

E
HPSW HPSW T_D Discharge Temp. Sensor
T_D T_D T_S Suction Temp. Sensor
T_CT T_CT T_CO Cond Out Temp. Sensor
V_HG AC
s

INV LPS T_EI EVI In Temp. Sensor

INV
T_EO EVI Out Temp. Sensor
CH CH T_L T_L Liquid Tube Temp. Sensor
SV_L
T_CT Comp. Top Temp. Sensor
s T_A Ambient Temp. Sensor
V_ES V_ES V_AR SV_G Gas Pipe Service Valve
SV_L Liquid Pipe Service Valve

14
Heat Pump Introduction
Part Introduction – Major Components

E
3

IPM1
IPM2
4
2 2 2
2 3
s

E
1
1 4
1

s
1

Name Description
■ 2 types of inverter compressors
Compressors 1 ■ Vapor injection compressor & Flash injection compressor
When compressor operates, oil is discharged from the compressors.
Oil separator 2
To maintain proper compressor oil level.
Intercooler 3 1. To secure sub-cooling, 2. Vapor injection
4 To protect the compressor from liquid flood back operation, the accumulator collects liquid
Accumulator
refrigerant and allows only the gas to enter the compressor.

15
Heat Pump Introduction
Part Introduction – Valve & EEV

2 5
7 3

E
2

IPM1
IPM2
4 1
3 5
s 4

E
6
1

s
s 6
7

Name Type Function

Hot gas bypass valve 1 Solenoid To compensate severe low pressure drop.
4way valve 2 Solenoid To change operation mode of cooling and heating operation.
Main EEV 3 Stepper Motor To control refrigerant flow rate in heating operation.
EVI EEV 4 Stepper Motor To control refrigerant flow rate for sub-cooling.
EVI bypass valve 5 Solenoid To supply vapor refrigerant to compressor suction.
Accumulator Oil Return Valve 6 Solenoid To recover oil from accumulator.
EVI Sol valve 7 Solenoid To inject vapor into the compressor scroll.

16
Heat Pump Introduction
Part Introduction – Sensor & Switch
4 5
6
10
9

E
10
83
4

IPM1
IPM2
11 3
2 6
7 1 2
1 9 8
3 3 s

E
1 1
5 2 2

s
7
s

Name Type Name Type

Discharge temp. sensor 1 200K ohm Tube temp. sensor 7 10K ohm

Top temp. sensor 2 200K ohm EVI in sensor 8 10K ohm

High pressure switch 3 - EVI out sensor 9 10K ohm

High pressure sensor 4 - Suction temp. sensor 10 10K ohm

Ambient air temp. sensor 5 10K ohm Low pressure sensor 11 -

Cond. out temp. sensor 6 10K ohm

17
Heat Pump Introduction
Part Introduction – Sensor & Switch

Name Type Description

Discharge temp. sensor 200K ohm To sense compressor discharge gas temperature

Ambient temp. sensor 10K ohm To sense outside ambient temperature

Cond_out temp. sensor 10K ohm To sense condensing outlet temperature.

EVI in/out temp. sensor 10K ohm To sense the temperature of vapor injection refrigerant

Liquid tube temp. sensor 10K ohm To sense the sub-cooled refrigerant temperature.

Suction temp. sensor 10K ohm To Sense compressor suction gas temperature

Name Description Output

To sense high pressure.
DC voltage
High pressure sensor To control fan RPM in cooling operation.
0 ~4.5V
To control compressor capacity in heating operation.
To sense low pressure temperature
DC voltage
Low pressure sensor To control compressor capacity in cooling operation
0 ~4.5V
To control fan RPM in heating operation

18
 DVM S
VRF Heat Recovery Introduction
Heat Recovery Introduction Name
INV Inverter Compressor
Heat Recovery Refrigerant Circuit – 1 Fan 1 compressor unit OFM Outdoor Fan Motor
OHX Outdoor Heat Exchanger
AC / OS Accumulator / Oil Separator
IC / IPMC Intercooler / IPM Cooler
CV_MC SV_HG CH Crank Case Heater
OFM
T_A HPS High Pressure Sensor
V_MC
s

CV_H T_CO LPS Low Pressure Sensor

OHX HPSW High Pressure Switch
E_M / E_EV Main EEV / EVI EEV

s
V_OE V_HG2 V_MC Main Cooling Valve

s
E_M V_ES EVI Sol. Valve

E
CV_E V_EB EVI Bypass Valve
V_4W T_S1 V_HG1 Hot Gas Bypass Valve 1
V_HG2 Hot Gas Bypass Valve 2
HPS V_4W 4Way Valve
SV_LG V_AR Accumulator Oil Return Valve
V_EB
CV_D s T_EO V_OE Outdoor EEV Valve
T_EI CV_E EEV Bypass Check Valve
IC CV_D Discharge Check Valve

E
OS E_EV CV_H HR Check valve
T_S2
CV_MC Main Cooling Check Valve
HPSW T_D Discharge Temp. Sensor
T_D IPMC
T_S1 Suction Temp. Sensor 1
T_CT V_HG1
T_S2 Suction Temp. Sensor 2
AC
LPS T_CO Cond Out Temp. Sensor
s

INV T_L T_EI EVI In Temp. Sensor

CH T_EO EVI Out Temp. Sensor
SV_L T_L Liquid Tube Temp. Sensor
s V_AR T_CT Comp. Top Temp. Sensor
V_ES T_A Ambient Temp. Sensor
SV_HG High Gas Pipe Service Valve
SV_LG Low Gas Pipe Service Valve
SV_L Liquid Pipe Service Valve

20
Heat Recovery Introduction Name
INV Inverter Compressor
Heat Recovery Refrigerant Circuit – 2 Fan 1 compressor unit OFM Outdoor Fan Motor
OHX Outdoor Heat Exchanger
AC / OS Accumulator / Oil Separator
IC / IPMC Intercooler / IPM Cooler
CH Crank Case Heater
SV_HG HPS High Pressure Sensor
CV_MC OFM OFM
T_A LPS Low Pressure Sensor
V_MC HPSW High Pressure Switch
s

CV_H T_CO
OHX E_M / E_EV Main EEV / EVI EEV
V_MC Main Cooling Valve

s
V_ES EVI Sol. Valve
V_OE V_HG2

s
E_M V_EB EVI Bypass Valve

E
V_HG1 Hot Gas Bypass Valve 1
CV_E V_HG2 Hot Gas Bypass Valve 2
V_4W T_S
V_4W 4Way Valve
HPS V_AR Accumulator Oil Return Valve
V_OE Outdoor EEV Valve
V_EB SV_LG
CV_E EEV Bypass Check Valve
CV_D s T_EO
T_EI CV_D Discharge Check Valve
IC CV_H HR Check valve

E
E_EV CV_MC Main Cooling Check Valve
OS T_S2 T_D Discharge Temp. Sensor
HPSW T_S1 Suction Temp. Sensor 1
T_D V_HG1 IPMC T_S2 Suction Temp. Sensor 2
T_CT T_CO Cond Out Temp. Sensor
LPS AC T_EI EVI In Temp. Sensor
s

INV T_L T_EO EVI Out Temp. Sensor

CH T_L Liquid Tube Temp. Sensor
T_CT Comp. Top Temp. Sensor
SV_L
s V_AR T_A Ambient Temp. Sensor
V_ES SV_HG High Gas Pipe Service Valve
SV_LG Low Gas Pipe Service Valve
SV_L Liquid Pipe Service Valve

21
Heat Recovery Introduction INV
Name
Inverter Compressor
OFM Outdoor Fan Motor
Heat Recovery Refrigerant Circuit – Dual Fan 2 compressor unit OHX Outdoor Heat Exchanger
AC / OS Accumulator / Oil Separator
IC / IPMC Intercooler / IPM Cooler
SV_HG
CH Crank Case Heater
HPS High Pressure Sensor
CV_MC LPS Low Pressure Sensor
OFM T_A
V_MC HPSW High Pressure Switch
s

T_CO E_M / E_EV Main EEV / EVI EEV

CV_H
OHX V_MC Main Cooling Valve
V_ES EVI Sol. Valve
V_OE V_EB EVI Bypass Valve

s
E
E_M V_HG1 Hot Gas Bypass Valve 1
CV_E V_HG2
V_HG2 Hot Gas Bypass Valve 2
V_4W T_S V_4W 4Way Valve
Accumulator Oil Return
V_AR
Valve
HPS IPMC IPMC V_OE Outdoor EEV Valve
CV_E EEV Bypass Check Valve
CV_D CV_D CV_D Discharge Check Valve
OS OS SV_LG CV_H HR Check valve
T_S2
V_EB T_EI CV_MC Main Cooling Check Valve
s T_EO IC T_D Discharge Temp. Sensor
HPSW HPSW

E
E_EV T_S1 Suction Temp. Sensor 1
T_D T_D T_S2 Suction Temp. Sensor 2
T_CT T_CT V_HG
AC T_CO Cond Out Temp. Sensor
s

INV INV LPS T_EI EVI In Temp. Sensor

T_EO EVI Out Temp. Sensor
CH CH T_L T_L Liquid Tube Temp. Sensor
SV_L T_CT Comp. Top Temp. Sensor
s T_A Ambient Temp. Sensor
V_ES V_ES V_AR SV_HG High Gas Pipe Service Valve
SV_LG Low Gas Pipe Service Valve
SV_L Liquid Pipe Service Valve

22
Heat Recovery Introduction
Part Introduction – Major Components

s
E
4
3

2 2 2
2 3
s

E
1

s
1 1
4
1

Name Description
■ 2 types of inverter compressors
Compressors 1
■ Vapor injection compressor & Flash injection compressor
When compressor operates, oil is discharged from the compressors.
Oil separator 2
To maintain proper compressor oil level.
Intercooler 3 1. To secure sub-cooling, 2. Vapor injection
To protect the compressor from liquid flood back operation, the accumulator collects
Accumulator 4
liquid refrigerant and allows only the gas to enter the compressor.

23
Heat Recovery Introduction
Part Introduction – Valve & EEV
4

s
3 6 5

s
8 2

s
E
4 3
1

5
2 6
s
7

E
1

s
s 7
8

Name Type Function

Hot gas bypass valve 1 1 Solenoid To compensate severe low pressure drop.
Hot gas bypass valve 2 2 Solenoid To equalize high & low pressure on unit stop
4way valve 3 Solenoid To change Heat/Cool operation mode – Energizes for heat operation.
Main cooling valve 4 Solenoid To supply refrigerant to heating indoor unit in main cooling operation.
Outdoor EEV valve 5 Stepper Motor To control refrigerant flow rate in main cooling operation.
EVI bypass valve 6 Solenoid To supply vapor refrigerant to compressor suction.
Accumulator Oil Return Valve 7 Solenoid To recover oil from accumulator.
EVI Sol valve 8 Solenoid To inject vapor to scroll.

24
Heat Recovery Introduction
Part Introduction – Valve & EEV

s
1

s
E
2
1

s 2

E
s
s

Name Type Function

Outdoor main EEV 1 Stepper Motor To control refrigerant flow rate in heating operation.
EVI EEV 2 Stepper Motor To control refrigerant flow rate for sub-cooling.

25
Heat Recovery Introduction
Part Introduction – Sensor & Switch
5

s
4 6
10

s
E
11 10
9 4
8
3 12
3
7 2 11 8
1 6 9
2 3 s
1

E
1
2
5

s
12 7

Name Type Name Type

Discharge temp. sensor 1 200K ohm Tube temp. sensor 7 10K ohm
Top temp. sensor 2 200K ohm EVI in sensor 8 10K ohm
High pressure switch 3 - EVI out sensor 9 10K ohm
High pressure sensor 4 - Suction temp. sensor 1 10 10K ohm
Ambient air temp. sensor 5 10K ohm Suction temp. sensor 2 11 10K ohm
Cond. out temp. sensor 6 10K ohm Low pressure sensor 12 -

26
Heat Recovery Introduction
Part Introduction – Sensor & Switch

Name Type Description

Discharge temp. sensor 200K ohm To sense compressor discharged gas temperature

Ambient temp. sensor 10K ohm To sense outdoor ambient temperature

Cond_out temp. sensor 10K ohm To sense condenser outlet temperature.

EVI in/out temp. sensor 10K ohm To sense vapor injection refrigerant temperature

Liquid tube temp. sensor 10K ohm To sense sub-cooled refrigerant temperature

Suction temp. sensor 10K ohm To sense compressor suction gas temperature

Name Description Output

To sense high pressure.
DC voltage
High pressure sensor To control fan RPM in cooling operation.
0 ~4.5V
To control compressor capacity in heating operation.
To sense low pressure
DC voltage
Low pressure sensor To control compressor capacity in cooling operation
0 ~4.5V
To control fan RPM in heating operation

27
Heat Recovery Introduction
Mode Change Units – S*NEK

Heat Recovery – MCU Mode Change Unit

 1,2,4&6 port models (max. 8 indoor units per port)
 Brazed pipe connections
 Main 3-pipe connection on both sides of MCU for series installation
 Excl. S1NEK single port MCU – right side connection only
 No condensate drain
 Auto addressing

S1NEK1N S2NEK2N S4NEK3N S6NEK2N

27
Heat Recovery Introduction
Mode Change Units – S*NEK

Low pressure gas

Refrigerant pass
through design
2,4&6 port models High pressure gas

Liquid

Liquid & dual pressure gas ports to indoor units

28
Heat Recovery Introduction
Cooling Operation  Hot gas bypass valve 2 open condition
 20 mins. In cooling
 Cooling oil recovery
 System stop in 2 mins. 30 sec. 30 sec. open then close
(pressure equalization)

E
s

s
E
E

s
E

E
s

s E

E
Low temperature & pressure gas
High temperature & pressure gas
High temperature & pressure liquid

28
Heat Recovery Introduction
Video

30
Heat Recovery Introduction
Main Cooling Operation
Cooling

E
s

s
E
E

Heating
s E

E
s

s E

E
Low temperature & pressure gas
High temperature & pressure gas
High temperature & pressure liquid

29
Heat Recovery Introduction
Video

32
Heat Recovery Introduction
Heating Operation
Heating

E
s

s
E
E

s E
E
s

s E

E
Low temperature & pressure gas
High temperature & pressure gas
High temperature & pressure liquid

30
Heat Recovery Introduction
Video

34
Heat Recovery Introduction
Main Heating Operation
Heating

E
s

s
E
E

Cooling
s E
E
s

s E

E
Low temperature & pressure gas
High temperature & pressure gas
High temperature & pressure liquid

31
Heat Recovery Introduction
Video

36
 DVM S
Indoor Unit Control
Indoor Unit Control
Indoor Unit Component Diagram
IDU Controlled Devices
 Fan – On/Off & Speed
 Electronic Expansion Valve Example: 4-Way Cassette PCB
 Condensate Lift Pump (specific units)
Coil outlet sensor
Control Components
(Gas)
 Temperature thermistor sensors
 Main PCB
 Remote Controller (wired or wireless) I
N
FAN D
O
Return air
O
sensor
R

Discharge sensor C
O
I Example: MWR-WE11N
NOTE: Discharge
EEV L
sensor is optional
on ducted IDU’s
Coil inlet sensor
(Liquid)

38
Indoor Unit Control
Fan Speed Control
 Fan speed control step

User control

- Ultra Low: minimum step( * non feedback type : 5 step + Low step x 0.25)
System - Low Low: Low – 1 step ( * 1step : about 20rpm)

control - High High: High + 1 step

- Ultra High: High + 2 step

 Quiet Mode reduces the sound level from the fan motor during cooling or heating operation
 Fan feedback indoor unit (ex. RAC, 1way, 2way, 4way) - Current Fan speed -1 step (1step = about 20 rpm)
 Fan non feedback indoor unit (ex. duct) - H  M , M  L , L  L

39
Indoor Unit Control
Fan On/Off Control – Thermo-off Condition

“02” SEG4 “02” External Minimizing

Mode Thermo EEV Fan
setting SEG 4 room s/s fan operation

ON Open On 0,1,2,3 0 Disuse Disuse

Cooling Closed On 0,1,2,3 1 Use Disuse
OFF
(0 or 35) Off 4,5,6,7 2 Disuse Use-Heating
ON Open On 0
3 Use Use-Heating
Off & On(20°F↑) 0,4
4 Disuse Use-Cooling
Heating Off & On 5 Use Use-Cooling
Open
OFF (20°F↑, 20sec on 2,6
120 step
every 5mins) 6 Disuse Use-Both

Off 1,3,5,7 7 Use Use-Both

40
Indoor Unit Control
Fan Speed Control – Cold Air Prevention (Heat Mode)
 On a heat thermo-On, the fan operation is delayed until the indoor coil reaches 82.4°F
 This is a default function and cannot be deactivated
Indoor coil Airflow in heating mode
temperature.
High or lower
100.4°F

96.8°F
Mid or lower High or lower
93.2°F

Low
89.6°F

86°F Mid or lower

Low Low
82.4°F
Fan off Low
79°F

Low Low
68°F
Fan off

41
Indoor Unit Control
Cool & Heat Thermo On & Off Operation

 Cooling Operation on Thermo on

Thermo on : Room temp. ≥ Set temp. Tset

Thermo off : Room temp. ≤ Set temp. -1 Tset-1

Thermo off Thermo off

Thermo off

 Heating Operation Thermo off

Tset + T°F
Thermo on : Room temp. ≤ Set temp. - 1 + T°F
Tset-1 + T°F
Thermo off : Room temp. ≥ Set temp. + T°F
Thermo on
on

42
Indoor Unit Control
Heating Compensation Temperature

 T°C = Heating compensation temperature

 Factory default (product code SEG6)
 4-Way type: T℃ = 9°F
 Others: T℃ = 3.6°F

 Installation Setting (option code SEG21)

 When using remote controller built-in room sensor – Installation option: SEG4=1
 T℃ = 0°F

 When wired R/C built-in sensor is set as “use” then T℃ = 0°F regardless of SEG4 setting
 Priority: Wired R/C built-in sensor use = Ext. Room Sensor setting > Installation Option >
Product Option
 If higher priority setting is applied, lower will be ignored

43
Indoor Unit Control
Indoor Unit Operation Mode
Mode Fan speed EEV Setting temp. range Remark

Fixed – Auto
18~30℃
Auto mode Difference between Set temp. & Room temp.) Control User selection
(65~86℉)
Low: 1°F ≤ Mid ≤ 3°F : High

User input 18~30℃

Cooling mode Control User selection
(Low, Mid, High, Auto) (65~86℉)

Fixed - Auto 18~30℃

Dry mode Control User selection
(Low / Low Low) (65~86℉)

User input 16~30℃

Heating mode Control User selection
(Low, Mid, High, Auto) (61~86℉)

Turbo mode Operating for 30mins

Fixed – High or Turbo Control Unable
(while Cooling/Heating) then return to previous

User input Fixed

Fan mode - User selection
(Low, Mid, High) (Close)

Fixed
Defrost Stop - System
(Open)

Turn on: User selected

Oil recovery Control - System
Turn off: Stop

44
Indoor Unit Control
Indoor Coil Freeze Protection Control
 Purpose: To prevent indoor coil freeze up due to abnormally low coil temperature
 Process: Hz Hold Hz Down HP Down (no error code for freeze protection)
Start

Evap temp＜35.6°F for 40 sec.

Hz Hold

Evap temp＜ 32°F for 40 sec.

Evap temp＞ 39.2°F → Return to normal control
After 2 min. Evap temp ≥ 32°F → Holding current Hz
Hz down
Evap temp＜ 32°F → 5Hz down
* Minimum Hz : HGV on
Evap temp＜ 28.4°F for 40 sec.

HP down Evap temp ＞ 39.2°F → Return to normal control

END

45
Indoor Unit Control
Auto Mode - Default
 Initial operation mode determination
If Room Temp. ≥ Set Temp. – 1°F If Room Temp. < Set Temp. – 1°F
 Auto cooling mode  Auto heating mode

 Thermo-On/Off
 Thermo-On/Off is same in cooling & heating mode

 When mode change is carried out

Model Heat pump Heat recovery
Condition 1&2&3 1 or 2 or 3

1. Thermo off for 30 mins

2. Only 1 IDU is turned on.
3. IDU product option change 1. Thermo off for 30 mins
“Seg 5 current + 2” 2. IDU Set temp. change
Detail
ex) 014046-194XXX  014066-194XXX 3. Follow the installation option setting
* refer to the next page for “3”
* If more than 2 IDUs are turned on, IDU mode
will follow the ODU operation mode.

46
Indoor Unit Control
Auto Mode – Auto Changeover Setting For Heat Recovery

A B C

D T

47
Indoor Unit Control
Auto Mode – Auto Changeover Setting For Heat Recovery
Setting Value 0 1 2 3 4 5 6 7
A Heating offset SEG4 0 0.5 1 1.5 2 2.5 3 3.5
B Cooling offset SEG5 0 0.5 1 1.5 2 2.5 3 3.5
C Heat  cool SEG6 1 1.5 2 2.5 3 3.5 4 4.5
D Cool  heat SEG8 1 1.5 2 2.5 3 3.5 4 4.5
T Time SEG9 5 7 9 11 13 15 20 30

Cooling thermo on
Start (Tr≥71.6+2+1°F)
77°F
75.2°F Cooling Thermo off
(Tr<71.6+2-1°F) Heating Thermo off
73.4°F
Cooling start (Tr≥71.6-1+1°F)
Tset= 71.6°F
Heating start
69.8°F
(Tr<71.6-1+1°F)
68°F
Heating Thermo on
66.2°F
(Tr<71.6-1-1°F)

Mode change : cool  Heat

20mins
(Tr<71.6-3 & 20mins thermo off)

48
Indoor Unit Control
Mixed Operation Prevention – Heat Pump only
Mixed operation prevention in wired remote controller
 Operation mode restriction by outdoor unit’s mode in Heat Pump
 If the wireless remote controller is in the opposite mode, the signal will be ignored

Stop Stop
Cool Stop Cool Stop or On
or On
Cool Thermo on/off Cool Thermo on/off
previous mode
Turn on heat mode Change to previous mode automatically
※ ODU cool - IDU can be auto, cool, dry, fan, stop
※ Previous mode was “heat” - IDU Stop in 1mins

Stop Auto
Cool Stop Cool Stop
or On Cool
Cool Thermo on/off Cool Thermo on/off
Turn on Auto mode
Follow to ‘auto cool’ or ‘auto heat’ by outdoor unit’s mode

Stop
Cool Stop Cool Stop Fan
or On
Cool Thermo on/off Cool Thermo on/off
Turn on Fan Fan mode is available any time regardless of mode

49
Indoor Unit Control
Mixed Operation Prevention – Heat Pump only
Mode master in wired remote controller
 Operation mode restriction by “Mode master indoor unit” even when the unit is stop
 If IDU is On or mode changed then mode will be determined by “mixed operation prevention”

Stop
Fan Stop or Fan Stop
cool Heat Heat
Cool
Turn on Heat mode Fan mode is available any time regardless mode

Stop
Auto Cool Stop or Auto
cool Heat
Stop
Cool Heat
Thermo on/off Heat
Turn on Heat mode
If current mode is auto then change to ‘auto cool’ or ‘auto heat’

Auto
Stop Cool Stop Cool
Cool Stop or Cool
Cool cool
Thermo on/off
Turn on Auto Follow ODU mode auto mode follows ODU mode

50
Indoor Unit Control
Electronic Expansion Valve Control
EEV fully closed  Refrigerant stop
gas

Cooling
ON OFF OFF ON

Condensed liquid

If EEV fully closed

↓
Refrigerant accumulation
EEV open slightly  Refrigerant flow ↓
refrigerant shortage in the system
Hot gas
EEV
EEV
120 step
Heating 0 step
ON OFF OFF ON

Condensed liquid

51
Indoor Unit Control
Condensate Lift Pump
 Cooling – Dry mode
Installation option 02

SEG8

Use of drain pump

Indication Details

0 Disuse

1 Use
3min delay option
Use+3min
2
delay

 Other mode Error (E153) : IDU stop, other IDU work as normal
ON
Float switch On More than 60sec
60s
OFF  Error release
Float switch Off

ON 3 min running
Drain pump On

Drain pump Off OFF

52
 DVM S
Outdoor Unit Control
Outdoor Unit Control
Control Logic Configuration
Self Check Reliability Control Special Operation Cycle Parts Control

Protect a unit Special operation Cycle parts control

Before starting,
from abnormal for more for optimal
self check starts
operation reliable system operation

EEPROM High Pressure Oil Return (Recovery) Compressor Capacity

Sensor open/Short Low Pressure Defrost FAN rpm

Communication Discharge Temperature Pressure balance EEV step

UP mode DSH Valve control

Leakage of Refrigerant Comp Over Current

54
Outdoor Unit Control
Basic Control Logic

Mode Main Part Output Factor Target

INV Comp FREQUENCY Low pressure (current-target) Target low pressure

Cooling OD FAN FAN STEP High pressure (current-target) Target high pressure

EVI EEV EEV STEP Sub-cool (current SC-target SC) Target SC/Td

INV Comp FREQUENCY High pressure (current-target) Target high pressure

OD FAN FAN STEP Low pressure (current-target) Target low pressure

Heating
Main EEV EEV STEP SH(Suc-Tst_LP), DSH, Balance, etc. Target SH

EVI EEV EEV STEP SH(EVI out-EVI in) Target SH/Td

55
Outdoor Unit Control
Compressor Safety Starting Pattern

Starting Crankcase Heater (CCH)

 CCH must be energized for 6 hours before initial compressor start to avoid damage due to
No liquid refrigerant forming in the compressor oil
Warm Start? Cold Start

Yes
No
Starting pattern
Normal
condition  Cold Start
 If the compressor temperature is low, a low start-up frequency is applied to protect the

Quick Start Normal Start compressor from potential liquid compression and poor lubrication due to oil foaming

 Cold operation
 If the DSH is low, the compressor frequency speed is decreased to protect the
compressor from liquid compression
No
DSH > 50°F Cold Operation
 Quick start
 All compressors start at the same time if required
Yes
 Normal start
Normal Operation
 Compressors start one after the other in sequence

DSH = Discharge Super Heat: Comp discharge temp minus high press saturated temp

56
Outdoor Unit Control
Normal & Cold Operation
 Limitation of max. frequency & frequency increasing speed until min. DSH is reached
 Low frequency operation
 Prevent accumulator liquid flooding

 DSH (Discharge Super Heat) = Compressor discharge temp. – High pressure saturated temperature

80
Mild Hz
Cold Operation condition (A || B ) 70
Normal operation
60
A DSH <50°F
50

B Max (T top, T dis) < 122°F 40 Cold operation

Cold Hz
30
MAX 30mins
* Judge when “Soft Start” finish 20 or
Max 3min 2min
10 DSH>15

Cold Start release (A || B ) 0

0 4 8 12 16 20
A Max 30 mins Pump Soft Mild
Down Start Start
B DSH >59°F

Safety start

57
Outdoor Unit Control
Cold Start
 Limitation of max. frequency & frequency increasing speed until min. DSH is reached
 Low frequency operation
 Oil forming prevention
 Secure compressor oil level

 DSH (Discharge Super Heat) = Compressor discharge temp. – High pressure saturated temp

Cold Start condition (A || B ) x C x D 80

70
A Max (T top, T dis) – T air < 59°F
60
B Max (T top, T dis) < 122°F

Frequency
50
C Less than 12 hours after the power supply 40
D Ambient temp. < 86°F (Cooling) 30 MAX 50 mins
or
Ambient temp. < 68°F (Heating) 20 DSH >15
10
Max=10 min 2min
Cold Start release (A || B )
0
A Max 50mins 0 4 8 12 16 20
Pump Soft Mild
B DSH > 59°F Down Start Start

Safety start

58
Outdoor Unit Control
Quick Start (≥ 30% Indoor Unit Capacity Required)
104 78.8

95 75.2
Room temp. (°F)

Room temp. (°F)

Heating Quick Start
86 71.6
Cooling Quick
68
77 Start
64.4
68
60.8
Ambient temp. (°F)
59 57.2
Ambient temp. (°F)
59 68 77 86 95 104 113 -13 -4 5 14 23 32 41 50 59

59
Outdoor Unit Control
Compression Ratio Control
 Purpose: Protect the compressor from abnormal operation  Compression Ratio
 Process: Hz Hold Hz Down HP Down Compressor stop (E428) = (High pressure + 14.7psi) / (Low pressure +14.7psi)
 Max. compression ratio: to limit capacity (Absolute pressure = Gauge pressure + 14.7psi)
 Min. compression ratio: to maintain lubrication

PSI. (Example) Compressor spec

640 Compression ratio
568.93 HP down
8.5
497.82
Hz down
426.7 7.4
Hz hold
355.6 7.0

284.47

213.35
SH (7°F) control
142.23
1.7
Minimum Hz limitation
71.12 1.5
0 Comp stop [E428]
PSI. 0 28.45 56.89 85.34 113.79 142.23 170.68 99.13 227.57

60
Outdoor Unit Control
Control Logic – Dual Compressors Starting

 Comp 2: Hz=Comp 1 + offset

 Offset: Max. 10 Hz Comp 2
 Major condition for next compressor starting (1or2)
 Comp. Hz > 76Hz Comp 1
 Comp. Hz > 60 Hz for 3 mins. Without unit stop
 Comp. Hz > 70 Hz for 3 mins. When unit stop

Control Logic – Additional Compressor Starting

Comp1 on + Comp 2 start
Comp 2 on + Comp 1 start
Comp 2
Comp 2

Comp 1
Comp 1

61
Outdoor Unit Control
Operating Priority
Main Sub 1 Sub 2 INV1 INV2
Modular System
2 or 3 ODU’s connected
together on the same
refrigerant network

 Master unit priority  Compressor priority in a unit

 At initial starting from power supply  Which one is off longer

 ODU address setting (Main - Sub1 - Sub2)  INV1 at initial starting from power supply

 Master unit rotation

 Additional compressor starting condition
 1- After defrost / oil recovery / all unit off
 Over 60Hz & over 3mins operation
(Master unit operates more than 60mins)
 Over 76Hz operation
 2 - Any unit is stopped over 40 min.
 Efficiency of 30~80Hz is better than higher
Main Sub1 Sub2
Master Sub1 Sub2 frequency
Sub2 Master Sub1
 Each unit will decide individually
Sub1 Sub2 Master

62
Outdoor Unit Control
Compressor Capacity Control
 Equal frequency in a unit: max. 10Hz difference
 Equal capacity in a module: Capacity division by unit capacity, control all compressor frequency difference
within 20Hz
38 HP System
Equivalent
Main unit Sub 1 unit
capacity in
(22HP) (16HP)
module

High efficiency
Oil balance 1 3 2 4

Equal Hz
in a unit

Example) Required capacity = 273,000 Btu/h

Main unit Sub 1 unit

Compressor Comp 1 (64cc) Comp 2 (64cc) Comp 1 (52cc) Comp 2 (52cc)
Module Capacity [Btu/h] 273,000: *22/38 = 158,000 273,000: *16/38 = 115,000
Comp Capacity [Btu/h] 79,000 79,000 57,500 57,500
Frequency 70 Hz 70 Hz + α 62 Hz 62 Hz + α

63
Outdoor Unit Control
System Pump Down – Cooling (Heat Pump)

To minimize liquid flood back in the system on next start, pump down or pump out is initiated after ODU stop

64
Outdoor Unit Control
System Pump Out – Heating (Heat Pump)

To minimize liquid flood back in the system on next start, pump down or pump out is initiated after ODU stop

65
Outdoor Unit Control
Heat Recovery – Operating Mode Determination
Main Cooling Mode Hysteresis A Heating Mode

Heating Capacity Ratio 0% 100 %

A% Criterion of HCR B%
Hysteresis range :
Max. range : -15% ~ 20% Cooling Mode Main Heating Mode
Hysteresis B
Ave. heating Indoor room temp. : 68°F
※ Heating capacity ratio = Σ(Heating) / {Σ(Heating) + Σ(Cooling)} Ave. cooling Indoor room temp. : 75.2°F
Indoor operating ratio : 50%

100
90
Criterion of HCR 80
70
 Value to decide mode of Heat Recovery

HCR[%]
60
 Factor : Ambient temp. IDU’s operating ratio, room temp. 50
40
30
Mode changeover in hysteresis
20
 Remaining 30 min in hysteresis area, mode changeover carry out 10
0
Outdoor Temp[°F]
5 14 23 32 41 50 59 68 77 86 95104 113 122

66
Outdoor Unit Control
Capacity Control - Cooling
Compressor frequency is controlled by the target low pressure which is changed by the averaging of evaporator inlet temperature

Low pressure < Target low pressure < Low pressure

Excessive capacity Insufficient capacity Target low pressure (psi)

85.34 92.45 99.56 106.68 113.78 120.89 128
Comp Hz down Comp Hz up

Capacity decreasing Capacity increasing * Default value of target low pressure: 113.78 psi

Hz Down - avg. evap. Inlet temp. = setting  target low press maintain
Target low pressure - avg. evap. Inlet temp. < setting  target low press increase
Hz Up Hz Up - avg. evap. Inlet temp. > setting  target low press decrease

Why is evaporator inlet temp used to find target low pressure?

 To compensate piping length between the ODU and IDU’s ODU Option Settings (Capacity correction)
Seg1 Seg2 Seg3 Seg4 Temperature
0 0 45°- 48°F
0 1 41°- 45°F (Default)
0 2 48°- 52°F
Main
L.P :118 psi L.P : 122 psi L.P : 127 psi 0 1 0 3 50°- 54°F
ODU
0 4 52°- 55°F
Evap in : 46°F Evap in : 48°F Evap in : 50 °F 0 5 54°- 57°F
L.P : 113.78 psi 0 6 55°- 59°F

67
Outdoor Unit Control
Capacity Control - Heating
High pressure < Target high pressure < High pressure

Seg1 Seg2 Seg3 Seg4 Pressure (psi)

Insufficient capacity Excessive capacity 0 0 426.7(default)
0 1 355.6
Comp Hz up Comp Hz down 0 2 369.8
Target high pressure control
0 3 384
Capacity increasing Capacity decreasing ODU option setting Main 0 2 0 4 398.25
0 5 412.48
Hz down 0 6 440.9
0 7 455.15
Target high pressure 0 8 469.4
Hz up Hz up

High pressure
Ex) option : 00 Ex) option : 02
122°F
(435 psi : saturated temp ≒ 122°F) (377 psi : saturated temp ≒ 111°F)

111F

H/X
H/X
Out

Out
Air
Air

Air
Air
In

In
68
Outdoor Unit Control
Outdoor Unit Fan Control

Cooling
Target high pressure
Fan rpm increase ODU setting
for cooling
Default 355.6 psi
Target high pressure ODU lowest setting
Fan rpm decrease 398.25 psi
Menu08 / value03

Heating Target low pressure

Ambient temp. (°F)
for heating
Fan rpm decrease Below 32 106.7 psi
32 ∼ 50 116.63 psi
Target low pressure
Fan rpm increase 50 ∼ 68 119.47 psi
68 ∼ 123.74 psi

69
Outdoor Unit Control
EVI – EEV Control
Purpose: To increase sub-cool of system : Sub-cool ↑  Efficiency ↑

Valve EVI EEV EVI Sol EVI Bypass *Condition

E
EVI Bypass
Open Open Open Normal

IPM1
IPM2
mode
EVI On mode All comp in unit 60hz ↑ 3
s
(Vapor Open Open Close T out < 96.8(c)/50(h)°F 1

E
Injection) * Control by unit

s
EVI Off Safety start
Close Open Open
mode Defrost s
2

Cooling Vapor injection not working when

ODU option 8 : ODU higher
EVI mode Cooling Heating ODU option 9 : Long pipe
▷ SH control
EVI
Bypass 1. EVI out temp. – EVI In temp. > 50°F (priority)
▷ Sub-cooling control : 68°F
mode 2. T dis = 194°F
( High pressure Saturated temp. – Liquid tube temp.)
EVI ▷SH ( EVI out temp. – EVI in temp.) control : 3.6°F
On(Vapor
Injection)
mode

Remark If compressor discharge temp. is abnormally high, open EVI EEV to decrease the discharge temperature

70
Outdoor Unit Control
Main EEV Control - Heating
EEV control period : every 20s
In heating mode
▶ Main EEV control
① Stop ODU : Main EEV close
DSH normal No
② Cooling ODU : Main EEV Full open
Yes DSH protection control

Module installation No
▶ Main EEV control for module install
Yes
1. Refrigerant distribution between ODUs
Low pressure equal No
2. Then Super Heat control (SH)
between ODUs
3. If discharge temp is high  EEV step
Yes
Target SH control
increases
Low pressure equalization control
Single install : 35.6°F

Target SH control
* SH = super heat Module install : 41°F
(Suction temp. – Low pressure saturated temp.)
* DSH = Discharge super heat EEV control repeat
(discharge temp. – high pressure saturated temp.)

71
Outdoor Unit Control
Accumulator Oil Return Valve - ARV
From EVI EEV

4Way valve Refrigerant

Compressor ARV control

Stop Close - Prevent refrigerant flowing to compressor

Starting Close - Prevent refrigerant flowing to compressor

Oil
Running Open - Oil return to compressor
ARV

oil
NOTE: Compressor damage can occur if the ARV fails
due to a lack of compressor oil return

72
Outdoor Unit Control
Compressor Oil Recovery Operation
 Oil recovery operation starts after a cumulative compressor run time of 7 hours
 The oil recovery interval will shorten if the outdoor unit or compressor stops
 If defrost mode is in operation for more than 3 minutes, it counts as oil recovery operation as well
 In a modular system (manifolded ODU’s) on completion of oil recovery operation the master ODU will change

Before Oil Recovery After Capacity of compressor Current capacity + additional capacity
ODU fan Normal control
Cooling Cooling Cooling ODU EEV Normal control
EEV of operating
Higher step of [400(C)/300(H) or Current step]
indoor units

Heating Heating Heating Stopped indoor unit’s

400(C)/300(H)
EEV
Time 3min(Cool) / 6min(Heat)

73
Outdoor Unit Control
Hot Gas Bypass Valve

 Hot gas bypass valve compensates

for abnormal low pressure
 Open status
 Safety start
 Low pressure protection control

E
IPM1

IPM2
Valve control Cooling Heating s

E
On (psi) ≤ 45.51 ≤ 19.91
Off (psi) ≥ 59.74 ≥ 34.14

s
s

Hot Gas
bypass valve

74
Outdoor Unit Control
High Pressure Protection
 Purpose: To protect the compressor and system from excessive high pressure
 Process: Hz hold Hz down HP down Compressor stop (E407)

Compressor Stop = E407

High Pressure
568.93 psi
HP Down area
High Pressure
HP Down release
540.49 psi
Hz Down area
High Pressure
Hz Down release
526.26 psi
Hz Hold area
High Pressure
512 psi
Hz Hold release

Normal Operation
High Pressure
426.7 psi
Compressor Stop Release

75
Outdoor Unit Control
Low Pressure Protection
 Purpose: To protect the compressor and system from abnormal low pressure
 Process: Hz hold Hz down HP down Compressor stop (E410)
 Compressor stop release: 3 mins. & low pressure 64 (cool) / 42.67 (heat) psi
Auto restart (6 X max.)
Heating

Cooling Operation Outdoor temp. Pressure (psi)

Operation Outdoor temp. Pressure (psi) Over 32°F ≤ 42.67

Over 59°F ≤ 56.9 Hz Hold 32°F~14°F ≤ 28.45

Hz Hold
Less than 14°F ≤ 25.6
Less than 59°F ≤ 42.67
Over 32°F ≤ 31.29
Over 59°F ≤ 49.78
Hz Down Hz Down 32°F~14°F ≤ 22.76
Less than 59°F ≤ 35.56
Less than 14°F ≤ 17.07
Over 59°F ≤ 36.98 Over 32°F ≤ 25.60
HP Down
Less than 59°F ≤ 22.76 HP Down 32°F~14°F ≤ 17.07

≤ 11.38 for 3mins Less than 14°F ≤ 11.38

Comp Down [E410]
& dis temp 194°F↑
≤ 7.11 for 3mins
Comp Down [E410]
& dis temp 194°F ↑

76
Outdoor Unit Control
Discharge Temperature Protection
 Purpose: To protect the compressor and system from abnormal discharge temperature
 Process: ESC EEV Open Hz Hold Hz Down HP Down Comp Stop (E416)

Compressor Stop = E416

Discharge
Temp. 248°F

HP / Hz Down area
Discharge
Temp. 221°F HP Down release

Hz Hold area
Discharge
Temp. 212°F Hz Down release

EVI EEV Open

Discharge
Temp. 203°F Hz Hold release

Normal Operation
Discharge
Temp. 176°F Compressor Stop Release

77
Outdoor Unit Control
Intelligent Power Module (IPM)
 Purpose: Protect the IGBT (Insulated Gate Bipolar Transistor) module from damage
 IGBT is a 3 terminal power semiconductor device functioning as an electronic switch
 The switching function controls the compressor frequency rate which in turn creates heat

. Hz Hold: Hold current Hz (Hz reduction possible)

. Hz Down: Decrease 5 Hz / control period
IMP temperature . HP Down: Decrease 1 Hz / sec
Compressor stop(E400 / E500)

100 ℃
212°F
HP Down area Compressor stop(E400 / E500), if condition remains for 10 min.

98℃
208°F HP Down release

Hz Down area
199°F
93℃ Hz Down release
Hz Hold area
194°F
90℃ Hz Hold release Compressor stop release

Normal operation

78
Outdoor Unit Control
Inverter PCB Input Current Control

Purpose: Inverter input current is controlled to protect circuit components from failure

INV PBA Input (A)

. Hz Hold: Hold current Hz (Hz reduction possible)

Compressor stop (E462) . Hz Down: Decrease 5 Hz / control period
Comp stop . HP Down: Decrease 1 Hz / sec

HP Down area
HP down HP Down release

Hz Hold area
Hz hold
Hz Hold release
(HP down – 1A)
Normal operation

79
Outdoor Unit Control
Current Control
 Purpose: To protect the IPM module from overheating
 Reason: Outdoor temp increases IPM temp increases Max. Hz limitation

In case of fan type

IPM Cooling
OD 113°F

Current [A]
Comp down
OD 104°F

OD 95°F
194°F 2A
Hz Hold Hz Down

Max HZ limitation
by IPM temp
Default Max Hz 86 122 OD temp. (°F)

80
Outdoor Unit Control
Maximum Current Control
 Outdoor Unit option setting: 50% - 100%
 Hz Hold: Compressor current + Fan current > 95% of setting current
 Hz Down: Compressor current + Fan current > setting current
 100%=Maximum current (MCA) of the system
 Setting: Outdoor unit option setting or DMS2 setting range (50% to 100%)
. Hz Hold: Hold current Hz (Hz reduction possible)
Max . Hz Down: Decrease 5 Hz / control period
current Setting of Max. current
. HP Down: Decrease 1 Hz / sec

HP Hold area
80% Required 100%
capacity
HP Hold area
Capacity range

95 %
Capacity range

50%
Range

81
Outdoor Unit Control
Inverter PCB Current Control

Inverter PCB input current is controlled to protect circuit components from failure

INV PCB Input (A)

Compressor stop (E462)

Comp stop

HP Down area
HP down HP Down release

Hz Hold area
Hz hold
Hz Hold release
(HP down – 1A)

Normal operation

82
Outdoor Unit Control
Refrigerant Overcharge - Cooling
 System will run in normal operation until it is above regulated capacity

High pressure protection control

High pressure will be increased

INV frequency goes to lowest setting
due to INV frequency increase

Increase sub cooling

High pressure
(Liquid piping temp decreases)

Keep constant low pressure

Low pressure
Low pressure is increased
When INV frequency decreases

Inverter
frequency

Increases INV frequency

to try to maintain low pressure

Overcharge condition progression

83
Outdoor Unit Control
Intelligent Defrost
Optimal judgement for initiating defrost operation

Btu/h MBtu/h
30000
102,000 30000
102,000
14°F heating 14°F heating Conventional
Conventional
Intelligent

68,000
20000 20000
68,000

34,000
10000 Defrost Defrost 10000
34,000

[min]
0 0 00
0 60 120 180 240 300 0 60 120 180 240 300
minutes
[Outdoor Temp. : 14°F DB, (Humidity 40%)]
[Outdoor Temp. : 14°F DB, (Humidity 40%)] [Indoor Temp. : 68°F DB]
[Indoor Temp. : 68°F DB]
Time & Temp & Sensing heat exchanger air resistance value
Time & Temp initiated defrost
 Continuous Heating operation
 Unnecessary defrost

84
Outdoor Unit Control
Intelligent Defrost
Test condition Test result

- Installation 24HP Outdoor for each zone.

* Only 2 defrost cycles for 10 days

Intelligent Normal Intelligent Conventional

Defrost Defrost Result
Defrost Defrost

24HP 24HP Total Operating time(min) 12,130 11,568

Defrost operation(times) 2 19

Average Heating Operation

6,065 608
without defrost(min)

85
Outdoor Unit Control
Rotation Defrost Operation - Heat Recovery
 Module systems (2 or 3 connected units) – Defrost operation is actuated in sequential order to improve heating efficiency
 Operation requires option setting at commissioning

Actuator Outdoor units in defrost mode Units not being in defrost mode
Depends on the outdoor unit capacity
Compressor General control
(86-110Hz)
Outdoor EEV Full close General control
Outdoor Fan 0 step General control
HR EEV Off General control
Main cooling
ON General control
valve
Active unit General control
Cooling indoor unit
Inactive unit Required step for control of the superheat degree
Indoor EEV
Heating Active unit General control
Indoor unit Inactive unit General control on inactive units
Active unit General control
Cooling indoor unit
Inactive unit Set fan speed
Indoor Fan
Heating Active unit Mid fan speed
Indoor unit Inactive unit Off
Time Maximum of 12 min -

86
Outdoor Unit Control
Rotation Defrost Operation - Heat Recovery

87