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Maintenance
Symptom
Compressor Short Cycles
Field Service
It may be necessary to perform repairs on the refrigeration
system. If field repairs are necessary, the following
procedures apply:
Note: Do not attempt to make repairs without the proper
tools.
Leak Detection
Several methods can be used to detect a leak in the
refrigeration system. The most modern and easiest
method is to use an electronic leak detector. Follow the
manufacturer's directions and any leak can be quickly
located. A second method is to use soap bubbles. Apply a
solution of soapy water with a brush or sponge to the
joints and connections in the refrigeration lines. A leak in
the lines will cause bubbles to form.
Leak Repair
When a leak is located, properly reclaim the remaining
refrigerant charge before attempting repairs. Adjacent
piping must be thoroughly cleaned by removing all paint,
dirt and oily film. Use a wire brush, sand cloth or sand
paper and wipe the area clean before attempting repair.
Protect nearby parts from heat damage by wrapping with
water-soaked cloths.
Refrigerant Piping
When replacing refrigeration components within the
cabinet of the unit, the following consumable materials
are recommended:
When brazing copper-to-copper connections (piping
liquid line or suction line), use a phosphorus copper
brazing alloy with 15% silver. General purpose silver
brazing alloy with 45% silver is to be used for copper-to-
brass or copper-to steel.
Wrap wet rags around the pipes between the areas to be
soldered and any nearby refrigeration components to
keep excessive heat from traveling through the pipe and
causing damage.
When component replacement is complete, remove all
traces of flux. After any repair, pressure check the system
to check for leaks prior to recharging the system.
26
Probable Cause
Low line voltage causing compressor to
overheat.
Dirty or iced over evaporator coil.
Reduced airflow (when applicable).
Lack of refrigerant.
Short cycling of conditioned air.
Remote temperature sensor is improperly
located.
General Common Repairs/Component
Replacement
Compressor Failure
The compressor is the most important component of the
RCU. Numerous safety devices are provided to protect the
compressor from failing.
If a compressor failure has occurred, determine whether it
is an electrical or a mechanical failure. An electrical failure
will be indicated by the distinct pungent odor once the
system has been opened. If a burnout has occurred, the oil
will be black and acidic. A mechanical failure will have no
burned odor and the motor will attempt to run, an
abnormal or excessive noise may be present.
An analysis of the oil is the only way to determine the
proper procedure for cleaning the refrigerant system. Acid
test kits are available from several manufacturers for
measuring the acid level in the oil. These are capable of
making accurate acid measurements, but if they are not
available, a check of the oil by sight and smell can give a
quick indication if contamination remains in the system.
Risk of Burns!
Avoid touching or contacting the gas and oil with
exposed skin. Severe burns will result. Use long rubber
gloves in handling contaminated parts.
All electrical connections should be checked to ensure
they are tight and properly made. Check all circuit
breakers, contactors and wiring. The contactors should be
examined and replaced if contacts are worn or pitted.
If there is acid in the oil, there has been an electrical failure
which has caused the compressor motor to burn out. The
acid diffuses throughout the refrigeration system and
must be removed by using a burnout filter kit before a new
compressor is placed in service. Not only must the
compressor be replaced, but also the entire refrigeration
circuit must be cleaned of the harmful contaminants left by
the burnout. Refer to
Procedure," p. 27
Recommendation
Check power source for cause of low line
voltage.
Defrost and clean evaporator/heat exchanger.
Check filter and belt tension.
Check for leak. Repair and recharge system.
Insufficient heat load. Increase heat load.
Check for supply registers that may be too close
to thermostat. Relocate if necessary.
WARNING
"Burn-Out/Acidic Cleanup
for the proper cleaning procedure.
SS-SVX004C-EN
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