AE4-1343

AE4-1343

January 2007
ZRHV72KJE AND ZBHV45KJE
VARIABLE SPEED HORIZONTAL SCROLLTM COMPRESSORS
INDEX

PAGE

1.

Introduction......................................................... 2

2.

Approved Refrigerants........................................ 2

3.

Inverter Operation............................................... 2

4.

Oil Type............................................................... 2

5.

Operating Envelopes.......................................... 3

6.

Discharge Temperature Protection..................... 4

7.

Internal Pressure Relief Valve............................ 5

8.

Pressure Controls............................................... 5

8.1

High Pressure Control........................................ 5

8.2

Low Pressure Control......................................... 5

9.

Accumulators...................................................... 5

10.

Screens............................................................... 5

11.

Crankcase Heaters.............................................. 5

12.

Pumpdown Cycle................................................. 6

13.

Minimum Run Time.............................................. 6

14.

Motor Protection.................................................. 6

15.

Electrical Connections......................................... 6

16.

Compressor Tubing and Mounting...................... 6

17.

Shell Temperature............................................... 6

18.

Connection Fittings............................................. 7

19.

Compressor Lifting Requirements...................... 7

20.

Rotation Direction............................................... 7

21.

Deep Vacuum Operation.................................... 7

22.

Brazing Procedure.............................................. 7

22.1

Unbrazing System Components......................... 8

23.

System Charging Procedure............................... 8

24.

High Potential (Hipot) Testing............................. 8

25.

Copeland Scroll Functional Check...................... 9

26.

Compressor Replacement after a Motor Burn.... 9

27.

Excessive Liquid Floodback Tests...................... 9

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AE4-1343

1. Introduction
Copeland Variable Speed Horizontal Scroll compressors
are designed for use in mobile and fixed air conditioning,
heat pump, and refrigeration applications. Typical model
numbers are ZRHV72KJE-TFD and ZBHV45KJE-TFD.
This bulletin describes the operating characteristics,
design features, and application requirements for
these models. Operating principles of the Copeland
Scroll are described in Copeland Application Engineering Bulletin 4-1312. The Horizontal Scroll compressor utilizes the same technology as the vertical
offerings but also incorporates a positive displacement
oil pump to enable horizontal operation. A variable
speed motor allows for precise matching of capacity to load and for efficient operation over a much
wider range than that of conventional fixed speed
compressors. In addition, an oil Schrader valve fitting and an oil sight glass are available on ZB models.
For additional information, please refer to the on-line product information accessible from the Emerson Climate Technologies website at www.emersonclimatecustomer.com.
2. Approved Refrigerants
ZRHV and ZBHV compressors are approved for use
with refrigerants R134a and R407C.
3. Inverter Operation
Since Copeland Horizontal Scroll compressors are
designed for mobile air conditioning applications, they
can operate on inverter-derived power. The variable

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speed ZRHV and ZBHV Copeland Horizontal Scroll

compressors can be operated over the range of 35-75
Hz. Compressor operating voltage must vary with frequency according to the guidelines shown in Figure 3.
The value of the voltage should be 7.67 multiplied by
the operating frequency over the range of 35 to 60 Hz.
From 60 to 75 Hz, the voltage should be a constant 460
volts. Matching voltage to frequency according to these
guidelines will prevent motor saturation and overheating.
Inverter drives used to power Copeland Horizontal
Scroll compressors must comply with the provisions
of IEC Technical Specification 600034-17. In particular, the motor input voltage must be limited to 1.35
kV/microsecond line-to-line impulse voltage. These
provisions are required to avoid motor insulation breakdown, to limit motor heating, and to prolong motor life.
4. Oil Type
Polyol ester lubricants must be used with HFC refrigerants R134a and R407C. Compressors using polyol
ester oil are identified with an E in the model number. An example is the ZRHV72KJE. For approved
lubricants see form number 93-11 titled, Copeland
Accepted Refrigerants/Lubricants. Any of the listed oils
may be used to recharge these compressors or if the
addition of oil is required. See compressor nameplate
for original oil charge. A complete recharge should be
four ounces (118 ml) less than the original oil charge.

AE4-1343

5. Operating Envelopes
Approved operating envelopes for the respective refrigerants are shown in Figure 1 and Figure 2. Note that the
operating envelopes are more restricted at lower speeds of operation. This is to prevent overloading and overheating of the compressor motor during low speed operation.

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AE4-1343

Figure 3. Voltage vs. Operating Frequency for ZRHV72KJE-TDF and ZBHV45KJE-TFD

500

450

Voltage

400

350

300

250
30

35

40

45

50

55

60

65

70

75

80

Frequency (Hz)

6. Discharge Temperature Protection

The horizontal compressor has no internal scroll temperature protection. As a result, an external discharge
line sensor is required for all refrigeration and heat
pump applications to provide loss of charge protection. This is because of the very low setting required
on the low pressure cutouts of these systems due to
their evaporating temperatures. Air conditioning systems do not always need the discharge line sensor.
The discharge line sensor is not normally required for
loss of charge protection when a low pressure cutout
with a setting of 25 psig (1.8 Kg/cm2) or higher can be
installed directly on the suction line of the compressor.
The following Loss-of-Charge test is recommended for
air conditioning systems to confirm that the existing
low pressure control provides the necessary protection: Operate the system in a 95F (35C) ambient
and monitor discharge line temperature while slowly
removing charge. If the discharge line temperature,
measured using an insulated thermocouple located 6
inches (15 cm) from the compressor, does not exceed
260F (127C) before the low pressure cutout trips, then
the system has adequate loss-of-charge protection. If
this is the case, then an external discharge line sensor
is not necessary. If the test shows that the discharge
temperature gets into the danger zone, then Emerson

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recommends the use of a thermistor sensor strapped

to the discharge line and insulated to provide discharge
temperature protection. The system controller must
lock out the compressor if the thermistor temperature
exceeds 260F (127C). As with the low pressure
cutout, the discharge temperature protection should
have a manual reset feature for the highest level of
protection. A minimum of a thirty-minute lockout period
should be provided for any discharge temperature trip.
Discharge line thermostats are available from Emerson
which provide adequate temperature protection in fixed
applications. Note that the kits shown in Table 1 are not
qualified for mobile applications.
Discharge Line Thermostat Kits
Kit Number

Conduit

Alarm Connector
Contact Lead

998-7022-02

Yes

No

998-0540-00

No

No

998-0541-00

No

Yes

Table 1

AE4-1343
sor for refrigerant and result in compressor failure. The
low pressure cut-out should have a manual reset feature
for the highest level of system protection. If a compressor is allowed to cycle after a fault is detected, there is
a high probability that the compressor will be damaged
and the system contaminated with debris from the failed
compressor and decomposed oil. If the compressor is fitted with a Rotalock valve, the low pressure switch MUST
be connected on the compressor side of the valve.

7. Internal Pressure Relief Valve

Horizontal scroll compressors do not have internal
pressure relief valves. To ensure safe operation, a
high pressure control must be used in all applications.
8. Pressure Controls
The Horizontal scroll compressors comply with the European Pressure Equipment Directive (PED) 97/23/EC.

9. Accumulators

Both high and low pressure controls are required and

should be wired in series with the compressor contactor
coil power supply. If a micro processor control is used,
it may monitor and lock out after a limited number of
trips. The following set points are the minimum and
maximum limits:

Refrigerant

High Pressure
Control

Low Pressure
Control

R134a

340 psig
(24 Kg/cm)

4 psig (0.3 Kg/cm)

R407C

425 psig
(30 Kg/cm)

The use of accumulators is very dependent on the

application. The Copeland Scrolls inherent ability to
handle liquid refrigerant during occasional operating
flood back situations makes the use of an accumulator
unnecessary in standard designs such as condensing
units. Applications such as heat pumps with orifice
refrigerant control, that allow large volumes of liquid
refrigerant to flood back to the compressor during
normal steady operation, can dilute the oil to such
an extent that bearings are inadequately lubricated,
and wear will occur. In such a case an accumulator
must be used to reduce flood back to a safe level that
the compressor can handle. To test for flood back
conditions and determine if the accumulator design is
adequate, please see Section 27 entitled Excessive
Liquid Floodback Tests at the end of this bulletin.
The accumulator oil return orifice should be from .040
to .055 inches (1 1.4 mm) in diameter depending on
compressor size and compressor flood back results.
A large-area protective screen no finer than 30 x 30
mesh (0.6 mm openings) is required to protect this small
orifice from plugging. Tests have shown that a small
screen with a fine mesh can easily become plugged
causing oil starvation to the compressor bearings.

25 psig (1.8 Kg/cm)

for A/C
7 psig (0.5 Kg/cm)
for heat pumps

Table 2
8.1 High Pressure Control
A high pressure control must be used with this
compressor. The high pressure control should
have a manual reset feature for the highest level of
system protection. Maximum cut out settings are
listed in Table 2. If the compressor is fitted with a
Rotalock valve, the high pressure switch MUST be
connected on the compressor side of the valve.

10. Screens
Screens finer than 30 x 30 mesh (0.6mm openings)
should not be used anywhere in the system with these
compressors. Field experience has shown that finer
mesh screens used to protect thermal expansion valves,
capillary tubes, or accumulators can become temporarily or permanently plugged with normal system debris
and block the flow of either oil or refrigerant to the compressor. Such blockage can result in compressor failure.

8.2 Low Pressure Control

Horizontal scroll compressors require a low pressure
control for loss of charge protection. If allowed to go undetected, loss of system charge will result in overheating
and damage to the scrolls and floating seal. Prolonged
operation with low charge will result in decomposition
of the oil that might require complete system replacement. Minimum cut out settings are listed in Table 2.

11. Crankcase Heaters

Crankcase heaters are normally the most effective
means of keeping liquid refrigerant out of the compressor oil during off cycles. In mobile applications, crankcase heaters are not effective since typically there will
not be voltage present during extended off cycle periods.
A check valve in the discharge line along with a liquid
line solenoid valve should be used to limit off cycle

The low pressure cut-out, if installed in the suction line

to the compressor, can provide additional protection
against a TXV failed in the closed position, a closed
liquid line service valve, or a blocked liquid line screen,
filter, orifice, or TXV. All of these can starve the compres-

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AE4-1343
migration to the compressor. The low leak check valve
must be qualified for discharge line service. A pumpdown cycle may be another option to limit migration.
12. Pumpdown Cycle
A pumpdown cycle may be used for control of refrigerant
migration. A separate external check valve must be
added to the discharge line if pumpdown is used.
The internal scroll discharge check valve is designed
to stop extended reverse rotation and prevent high
pressure gas from leaking rapidly into the low side
after shut off. The recommended external check valve
will prevent liquid refrigerant from returning to the compressor through the discharge line. The check valve
can also prevent frequent recycling due to leak-back.
If a microprocessor is used, the system can be set to pump
down for a fixed number of seconds after the setpoint is
reached and the liquid line solenoid valve is closed. The
exact time should be determined by testing. The system
should pump down until the pressure is close to the cutout pressure of the low pressure switch. It is not necessary to pump down into nearly a vacuum to remove all
liquid refrigerant from the low side. If the low pressure
switch opens, the pumpdown should stop immediately.
Copeland Scroll compressors trap a considerable volume of high pressure gas between the muffler plate
and the top cap. When the compressor shuts down, the
trapped gas will expand back into the suction side of
the system. This frequently causes a pulse of pressure
to propagate down the suction line and can cause the
low pressure switch to reset. The compressor must not
be allowed to short cycle which may result in oil pump
out. The electrical circuitry should be arranged so that
compressor restart is triggered by demand from the
thermostat rather than a reset low pressure switch.
13. Minimum Run Time
There is no set answer to how often scroll compressors can be started and stopped in an hour, since it is
highly dependent on system configuration. There is no
minimum off time, because the scrolls start unloaded,
even if the system has unbalanced pressures. The
most critical consideration is the minimum run time required to return oil to the compressor after startup.
14. Motor Protection
An internal line break motor protector, located in the
center of the Y of the motor windings, disconnects all
three phases in case of an overload or over-temperature
condition. The protector reacts to a combination of motor current and motor winding temperature. The internal
protector protects against single phasing. Time must be

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allowed for the motor to cool down before the protector will reset. If current monitoring to the compressor
is available, the system controller can take advantage
of the compressor internal protector operation. The
controller can lock out the compressor if current draw
is not coincident with contactor energizing, implying that
the compressor has shut off on its internal protector.
This will prevent unnecessary compressor cycling on
a fault condition until corrective action can be taken.
15. Electrical Connections
The orientation of the electrical connections on the
Copeland Scroll compressors is shown on the terminal
box gasket. Connection options are either a standard
quick-connect flag style or a push on molded plug style.
16. Compressor Tubing and Mounting
Compressor mounting must be selected based on
application. Consideration must be given to vibration
reduction and tubing reliability. Some tubing geometry
or shock loops may be required to reduce vibration
transferred from the compressor to external tubing.
Tubing Considerations - Proper tube design must be taken
into consideration when designing the tubing connecting
the Scroll to the system. The tubing should provide
enough flexibility to allow normal starting and stopping
of the compressor without exerting excessive stress on
the tube joints. In addition, it is desirable to design tubing
with a natural frequency away from the normal running
frequency of the compressor. Failure to do this can result
in tube resonance and unacceptable tubing life. Figure
6 is an example of acceptable tubing configurations.
Caution: These examples are intended only as guidelines to depict the need for flexibility in tube designs. In
order to properly determine if a design is appropriate for
a given application, samples should be tested and evaluated for stress under various conditions of use including
voltage, frequency, load fluctuations, and shipping vibration. The guidelines above may be helpful; however,
testing should be performed for each system designed.
17. Shell Temperature
Certain types of system failures, such as condenser or
evaporator fan blockage or loss of charge, may cause
the end shell and discharge line to briefly but repeatedly
reach temperatures above 350F (177C) as the compressor cycles on its internal protection devices. Care
must be taken to ensure that wiring or other materials,
which could be damaged by these temperatures, do
not come in contact with these potentially hot areas.

AE4-1343
18. Connection Fittings

reversed direction for a short period of time (under one

hour). After several minutes of operation in reverse, the
compressors internal protector will trip. If allowed to repeatedly restart and run in reverse without correcting the
situation, the compressor will be permanently damaged.

Scroll compressors are provided either with stub connections or Rotalock adapters depending on the bill of
material selected (consult your District Sales Manager
or Application Engineer for details). Stub tube models
have copper plated steel suction and discharge fittings for a more rugged, leak resistant connection.

All three phase scroll compressors are identically

wired internally. As a result, once the correct phasing is determined for a specific system or installation, connecting properly phased power leads to the
same terminals will maintain proper rotation direction.

Brazing procedures for copper plated steel fittings are

inherently different than brazing pure copper fittings.
See Section 22 entitled Brazing Procedure for suggestions on how to properly make these connections.

21. Deep Vacuum Operation

19. Compressor Lifting Requirements

A low pressure control is required for protection

against deep vacuum operation. See Section 8
entitled Pressure Controls for proper set points.
Copeland Scroll compressors (as with any refrigerant compressor) should never be used to evacuate
a refrigeration or air conditioning system. The scroll
compressor can be used to pump down refrigerant
in a unit as long as the pressures remain within the
operating envelope shown in Section 5. Low suction
pressures will result in overheating of the scrolls and
permanent damage to the compressor drive bearing.

Positioned on the topside of the compressor shell end

caps are lifting tabs. See Figure 4. It is very important
to utilize these lifting devices to maintain the compressor in the horizontal position during the installation and
removal. Otherwise, damage to the compressor could
occur.

22. Brazing Procedure

Figure 5 discusses the proper procedures for brazing
the suction and discharge lines to a Copeland Scroll
compressor. It is important to flow nitrogen through
the system while brazing all joints during the system
assembly process. Nitrogen displaces the air and prevents the formation of copper oxides in the system. If
allowed to form, the copper oxide flakes can later be
swept through the system and block screens such as
those protecting thermal expansion valves and accumulator oil return holes. The blockage - whether it is of
oil or refrigerant - is capable of doing damage resulting
in compressor failure.

Figure 4.
20. Rotation Direction of Three Phase Scroll Compressors
Scroll compressors will only compress in one rotational
direction. Three phase compressors will rotate in either direction depending upon phasing of the power.
Since there is a 50-50 chance of connecting power in
such a way as to cause rotation in the reverse direction, it is important to include notices and instructions
in appropriate locations on the equipment to ensure
proper rotation direction when the system is installed
and operated. Verification of proper rotation direction
is made by observing that suction pressure drops
and discharge pressure rises when the compressor
is energized. Reverse rotation of a scroll compressor also results in substantially reduced current draw
compared to specification sheet values. Suction temperature will be high, discharge temperature will be
low, and the compressor may be abnormally noisy.

Figure 5.

There is no negative impact on durability caused by operating three phase Copeland Scroll compressors in the

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AE4-1343
New Installations
The copper-coated steel tubes on scroll
compressors can be brazed in approximately the same manner as any copper tube.
Recommended brazing materials: Any Silfos material is recommended, preferably with a minimum
of 5% silver. However, 0% silver is acceptable.
Be sure both tube fitting I.D. and O.D. are clean prior
to assembly. If oil film is present wipe with denatured
alcohol, dichlorotrifluoroethane or other suitable solvent.
Using a double-tipped torch apply heat in Area 1.
As tube approaches brazing temperature, move torch
flame to Area 2.
Heat Area 2 until braze temperature is attained,
moving torch up and down and rotating around
tube as necessary to heat tube evenly. Add braze
material to the joint while moving torch around
joint to flow braze material around circumference.
After braze material flows around joint, move torch to
heat Area 3. This will draw the braze material down into
the joint. The time spent heating Area 3 should be minimal.
As with any brazed joint, overheating may
be detrimental to the final result.
Field Service
To disconnect: Reclaim refrigerant from both the high
and low side of the system. Cut tubing near compressor.
To reconnect:

when it escapes and contacts the brazing flame. To

prevent this occurrence, it is important to check both
the high and low side with manifold gauges before
unbrazing. Instructions should be provided in appropriate product literature and assembly (line repair) areas.
If compressor removal is required, the compressor
should be cut out of system rather than unbrazed.
23. System Charging Procedure
Systems should be charged with liquid on the high side
to the extent possible. The majority of the charge should
be pumped into the high side of the system to prevent
hipot failures and bearing washout during first time start.
If additional charge is needed, it should be added as liquid, in a controlled manner, to the low side of the system
with the compressor operating. Pre-charging on the high
side and adding liquid on the low side of the system are
both meant to protect the compressor from operating
with abnormally low suction pressures during charging.
Do not start the compressor while the system is
in a deep vacuum. Internal arcing may occur when
a compressor is started in a vacuum. Do not operate
compressor without enough system charge to maintain at least 7 psig (0.5Kg/cm) suction pressure. Do
not operate with a restricted suction. Do not operate
with the low pressure cut-out jumpered. Allowing
pressure to drop below 7 psig (0.5Kg/cm) for more than
a few seconds may overheat scrolls and cause early
drive bearing damage. Do not use compressor to test
opening setpoint of high pressure cutout. Bearings are
susceptible to high load damage before they have had
several hours of normal running for proper break in.

Insert tubing stubs into fitting and connect to the

system with tubing connectors.

Never install a system in the field and leave it unattended with no charge, a holding charge, or with the
service valves closed without securely locking out the
system. This will prevent unauthorized personnel from
accidentally running the system and potentially ruining
the compressor by operating with no refrigerant flow.

Follow New Installation brazing instructions.

24. High Potential (Hipot) Testing

Recommended brazing materials: Silfos with minimum 5% silver or silver braze material with flux.

22.1 Unbrazing System Components

Caution! Before opening a system it is important
to remove all refrigerant from both the high and
low side. If the refrigerant charge is removed from a
scroll-equipped unit by bleeding the high side only, it
is possible for the scrolls to seal, preventing pressure
equalization through the compressor. This may leave
the low side shell and suction line tubing pressurized.
If a brazing torch is then applied to the low side while
the low side shell and suction line contain pressure,
the pressurized refrigerant and oil mixture could ignite

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A hipot test is usually conducted on the production line by the manufacturer. This test can be
conducted in the field; however, field technicians
typically do not have the required equipment.
Copeland horizontal scroll compressors are configured with the motor at the same level as the pumping
components. As a result, the motor can be immersed
in oil and refrigerant to a greater extent than hermetic
reciprocating compressors when liquid refrigerant
is present in the shell. In this respect, the horizontal
scroll is more like semi-hermetic compressors which

AE4-1343
quence for compressors and systems can be found
in Section H of the Copeland Electrical Handbook.

can have horizontal motors partially submerged in oil

and refrigerant. When Copeland Scroll compressors
are Hipot tested with liquid refrigerant in the shell, they
can show higher levels of leakage current than compressors with the motor on top. This phenomenon can
occur with any compressor when the motor is immersed
in refrigerant. The level of current leakage does not
present any safety issue. To lower the current leakage
reading, the system should be operated for a brief period
of time to redistribute the refrigerant to a more normal
configuration and the system Hipot tested again. See
AE Bulletin 4-1294 for Megohm testing recommendations. Under no circumstances should the Hipot test be
performed while the compressor is under a vacuum.

7. Before replacing or returning a compressor: Be certain

that the compressor is actually defective. As a minimum,
recheck a compressor returned from the field in the
shop or depot for Hipot failure, winding resistance, and
ability to start before returning. More than one-third of
compressors returned to Copeland for warranty analysis
are determined to have nothing found wrong. They were
mis-diagnosed in the field as being defective. Replacing
working compressors unnecessarily costs everyone.
8. NEVER test a scroll compressor by closing the
suction valve or the liquid feed to the evaporator and pumping the compressor into a vacuum.

25. Copeland Scroll Functional Check

A functional compressor test with the suction service
valve closed to check how low the compressor will pull
suction pressure is not a good indication of how well
a compressor is performing. Such a test will almost
certainly damage a scroll compressor. The following
diagnostic procedure should be used to evaluate whether a Copeland Scroll compressor is working properly.

26. Compressor Replacement after a Motor Burn

In the case of a motor burn, the majority of contaminated
oil will be removed with the compressor. The rest of
the oil is cleaned through use of suction and liquid line
filter dryers. A 100% activated alumina suction filter
drier is recommended but must be removed after 72
hours. See Application Engineering Bulletin 24-1105 for
clean up procedures and AE Bulletin 11-1297 for liquid
line filter drier recommendations. It is highly recommended that the suction accumulator be replaced
if the system contains one. This is because the accumulator oil return orifice or screen may be plugged
with debris or may become plugged shortly after a
compressor failure. This will result in starvation of oil
to the replacement compressor and a second failure.

1. Proper voltage to the unit should be verified.

2. The normal checks of motor winding continuity
and short to ground should be made to determine if
the inherent overload motor protector has opened or
if an internal motor short or ground fault has developed. If the protector has opened, the compressor
must be allowed to cool sufficiently to allow it to reset.

27. Excessive Liquid Floodback Tests

3. Proper indoor and outdoor blower/fan operation

should be verified.

The following tests are for those system configurations

and charge levels identified in Table 4 that need special
testing to verify exemption from need of an accumulator.
Figure 7 should be used to determine the effectiveness
of an accumulator. The compressor sump temperature
during any test where the return gas superheat is near
zero must always meet the guidelines of Figure 7.

4. With service gauges connected to suction and discharge pressure fittings, turn on the compressor. If suction
pressure falls below normal levels, the system is either
low on charge or there is a flow blockage in the system.
5. If suction pressure does not drop and discharge pressure does not rise to normal levels, reverse any two of
the compressor power leads and reapply power to make
sure compressor was not wired to run in reverse direction.

To test for excessive continuous liquid refrigerant

flood back, it is necessary to operate the system in a
test room at conditions where steady state flood back
may occur (low ambient heating operation). Thermocouples should be attached with glue or solder to
the center of the bottom shell and to the suction and
discharge lines approximately 6 inches (15 cm) from
the shell. These thermocouples should be insulated
from the ambient air with Permagum or other thermal
insulation to be able to record true shell and line temperatures. If the system is designed to be field charged,
it should be overcharged by 15% in this test to simulate
overcharging commonly found in field installations.

6. To test if the compressor is pumping properly,

the compressor current draw must be compared to
published compressor performance curves using the
operating pressures and voltage of the system. If the
measured average current deviates more than 15%
from published values, a faulty compressor may be
indicated. A current imbalance exceeding 15% of the
average on the three phases should be investigated
further. A more comprehensive troubleshooting se-

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AE4-1343
Typical Suction Tubing

To test for repeated excessive liquid flood back during

normal system off-cycles perform the Field Application Test. This is particularly important if the evaporator
is positioned higher than the compressor in the final
installation. Obtain a sample compressor with a side
sight tube to measure liquid level in the compressor. Set
the system up in the same configuration as it would be
in the field with the evaporator positioned at a realistic
height relative to the compressor and condenser. Use
the normal length of connecting tubing between the
indoor and outdoor units. If the system is designed to
be field charged, the system should be overcharged
by 15% in this test to simulate overcharging commonly
found in field installations. Operate the system in the
cooling mode at the outdoor ambient, on/off cycle times,
and number of cycles specified in Table 3. Record the
height of the liquid in the compressor at the start of each
on cycle, any protector trips, or any abnormal sounds
during each test. Review the results with Copeland
Application Engineering to determine if an accumulator
is required for the application. The criteria for pass/fail
is whether the liquid level reaches a height above the
compressor mounting foot of 2.4 in (6 cm). Liquid levels
higher than this will allow the compressor oil floating on
top of the refrigerant to be ingested by the scrolls and
pumped out of the compressor.

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10

(d)

(0.5m)

The system should be operated at an indoor temperature of 70F (21C). and outdoor temperature extremes
(0F or -18C or lower) in heating to produce flood back
conditions. The compressor suction and discharge
pressures and temperatures as well as the sump temperature should be recorded. The system should be allowed to frost up for several hours (disabling the defrost
control and spraying water on the outdoor coil may be
necessary) to cause the saturated suction temperature
to fall to below -10F (-23C). The compressor sump
temperature must remain above the sump temperature
shown in Figure 7 or design changes must be made
to reduce the amount of flood back. If an accumulator
is used, an oil return orifice size of 0.040 - .055 (1
- 1.4mm) is recommended. (See information on Accumulators in Section 9 and also Copeland Application
Engineering bulletin 11-1247). Increasing indoor coil
volume, increasing outdoor air flow, reducing refrigerant charge, decreasing capillary or orifice diameter, and
adding a charge compensator can also be used to reduce excessive continuous liquid refrigerant flood back.

(b)

(f)

(c)
(0.5m)

(c) (e)

(g)

Figure 6.
NOTES:
(a) The above tubing configurations are guidelines to
minimize tube stress.
(b) Follow similar guidelines for the discharge tube.
(c) If a run of over 20 (0.5m) is required, intermediate
clamps may be necessary.
(d) Do not hang weights on tubing (e.g. filter drier on
suction tubing) except after clamps or close to the
header.
(e) Tube runs of less than 8 (0.2m) are not recommended.
(f) This dimension should be made as short as possible [e.g. 2 (50mm) or less] but still insuring a proper
braze joint.
(g) The above tubing recommendations are based
on no elbow joints. The use of continuous tubing is
preferred.

AE4-1343
Oil Dilution Chart

200F (93.3C) Max. Oil Temp.

Evaporating Temp. (C)

100

-20

-15

-10

-5

10

90
Compressor Sump Temp. (F)

Safe Area

70

OK
* See Note 1

20

60
10

50
40
Unsafe Area
(Too much refrigerant dilution)

30

20

Compressor Sump Temp. (C)

30
80

-10

10
0

-10

10

20

30

40

50

Evaporating Temp. (F)

Note 1: Operation in this refrigerant dilution area

is safe in air-to-air heat pump heating mode. For
other applications, such as AC only, review expansion device to raise superheat. A cold sump may
result in high refrigerant migration after shut down.
Figure 7

Field Application Test

Operate the system as it would be operated in an actual
field installation, cycling the unit on and off for the times
indicated at each ambient.
85F
(29C)

95F
(35C)

105F
(40C)

System On-Time
(Minutes)

14

54

System Off-Time
(Minutes)

13

Number of
On/Off Cycles

Outdoor Ambient

Table 3

1997 Emerson Climate Technologies, Inc.

Printed in the U.S.A.

11

 1997 Emerson Climate Technologies, Inc.

Printed in the U.S.A.

12
Not
Required
Required

Not
Required

Required

Other (1)

Required

Not
Required

Required

Other (1)

Required

Other (1)

Not
Required

Required

(1) Other" includes bleed-type TXVs, capillary tubes, and fixed orifices
(2) Nominal System Charge is defined as the design charge for a system
(* = 12 lbs (5.5 Kg))

Nominal
System
Charage
(2)

Required

Non-Bleed
TXV

Non-Bleed
TXV

Table 4
Scroll Compressor Application Diagram

Not
Required

Required

Not
Required

Other (1)

AE4-1343