Connection Fittings, Service Valves And Adapters; Deep Vacuum Operation; Unbrazing System Components; Hipot Testing - Emerson Copeland Scroll K5 Series Application Bulletin

Condensing Units – For 8 -15 HP Copeland Scroll
condensing unit applications, standard mounts (55-65
durometer) are recommended. The mounting system
for K5 refrigeration scroll condensing units is depicted
in Figure 7B.
Tubing Considerations – Proper tube design must be
taken into consideration when designing the tubing
connecting the scroll to the remaining system. The
tubing should provide enough "fl exibility" 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 2 is an example of an
acceptable tubing confi guration.
CAUTION
These examples are intended only as guidelines
to depict the need for fl exibility 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,
and load fl uctuations, and shipping vibration. The
guidelines above may be helpful; however, testing
should be performed for each system designed.
Connection Fittings, Service Valves, and Adapters
The fi tting sizes for 8 through 15 HP scrolls are shown
in Table 5.

Deep Vacuum Operation

WARNING
Do not run a Copeland Scroll compressor in a deep
vacuum. Failure to heed this advice can result in
arcing of the Fusite pins and permanent damage
to the compressor.
A low pressure control is required for protection against
deep vacuum operation. See Pressure Control section
for proper set points. (Table 6)
Scroll compressors (as with any refrigerant compressor)
should never be used to evacuate a refrigeration or air
conditioning system. See AE-1105 for proper system
evacuation procedures.

Unbrazing System Components

WARNING
If the refrigerant charge is removed from a scroll
unit by bleeding the high side only, it is sometimes
© 2012 Emerson Climate Technologies, Inc.
Printed in the U.S.A.
Application Engineering
B U L L E T
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, the pressurized refrigerant and oil mixture
could ignite as it escapes and contacts the brazing
fl ame. It is important to check both the high and low
sides with manifold gauges before unbrazing or in
the case of assembly line repair, remove refrigerant
from both the high and low sides. Instructions
should be provided in appropriate product literature
and assembly (line repair) areas.
High Potential (Hipot) Testing
Many of the Copeland brand compressors are confi gured
with the motor below the compressor. As a result, when
liquid refrigerant is within the compressor shell the motor
can be immersed in liquid refrigerant to a greater extent
than with compressors with the motor mounted above
the compressor. When Copeland brand compressors are
Hipot tested and liquid refrigerant is in the shell, they can
show higher levels of leakage current than compressors
with the motor on top because of the higher electrical
conductivity of liquid refrigerant than refrigerant vapor
and oil. 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 confi guration and the system
Hipot tested again. See bulletin AE4-1294 for Megohm
testing recommendations. Under no circumstances
should the Hipot or Megohm test be performed while the
compressor is under a vacuum.
Note: The solid state electronic module components
and internal sensors are delicate and can be damaged
by exposure to high voltage. Under no circumstances
should a high potential test be made at the sensor
terminals or sensor leads connected to the module.
Damage to the sensors or module may result.
Three Phase Scroll Compressors – Directional
Dependence
Scroll compressors are directional dependent; i.e. they
will compress in one rotational direction only. Three
phase scrolls will rotate in either direction depending
on power phasing. Since there is a 50/50 chance of
connected power being "backwards", contractors should
be warned of this. Appropriate instructions or notices
should be provided by the OEM.
Verifi cation of proper rotation can be made by observing
that the suction pressure drops and the discharge
pressure rises when the compressor is energized.
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AE4-1383 R5