Service Manual

29
FIRE HAZARD
Failure to follow this warning could result in personal
injury or equipment damage.
Cut tubing to reduce possibility of personal injury and
fire.
!
WARNING
8. Use asmalltubing cutter to cut the liquid and vapor
lines at both sides of coil. Cut in convenient location
for easy reassembly with copper slip couplings.
9. Lift coil vertically from basepan and carefully place
aside.
10. Reverse procedure to reinstall coil.
11. Replace filter drier, evacuate system, recharge, and
check for normal systems operation.
Compressor Removal and Replacement
Once it is determined that compressor has failed and the
reason established, compressor must be replaced.
PERSONAL INJURY HAZARD
Failure to follow this caution may result in personal
injury.
Turn off all power to unit before proceeding. Wear
safety glasses, protective clothing, and gloves when
handling refrigerant. Acids formed as a result of motor
burnout can cause burns.
CAUTION
!
CAUTION
!
PERSONAL INJURY HAZARD
Failure to follow this caution may result in personal
injury.
Wear safety glasses, protective clothing, and gloves
when handling refrigerant and when using brazing
torch.
1. Shut off all power to unit.
2. Remove and recover all refrigerant from system until
pressure gauges read 0 psi. Use all service ports.
Never open a system under a vacuum to atmosphere.
Break vacuum with dry nitrogen holding charge first.
Do not exceed 5 psig.
3. Disconnect electrical leads from compressor.
Disconnect or remove crankcase heater and remove
compressor hold- down bolts.
4. Cut compressor from system with tubing cutter. Do
not use brazing torch for compressor removal. Oil
vapor may ignite when compressor is disconnected.
5. Scratch matching marks on stubs in old compressor.
Make corresponding marks on replacement
compressor.
6. Use torch to remove stubs from old compressor and
to reinstall them in replacement compressor.
7. Use copper couplings to tie compressor back into
system.
8. Replace filter drier, evacuate system, recharge, and
check for normal system operation.
CAUTION
!
UNIT DAMAGE HAZARD
Failure to follow this caution may result in equipment
damage or improper operation.
Do not leave system open to atmosphere. Compressor
oil is highly susceptible to moisture absorption.
System Clean- Up After Burnout
Some compressor electrical failures can cause motor to
burn. When this occurs, by- products of burn, which include
sludge, carbon, and acids, contaminate system. Test the oil
for acidity using POE oil acid test to determine burnout
severity. If burnout is severe enough, system must be
cleaned before replacement compressor is installed. The 2
types of motor burnout are classified as mild or severe.
In mild burnout, there is little or no detectable odor.
Compressor oil is clear or slightly discolored. An acid test of
compressor oil will be negative. This type of failure is treated
the same as mechanical failure. Liquid- line strainer should
be removed and liquid- line filter drier replaced.
In a severe burnout, there is a strong, pungent, rotten egg
odor. Compressor oil is very dark. Evidence of burning may
be present in tubing connected to compressor. An acid test
of compressor oil will be positive. Follow these additional
steps:
1. TXV must be cleaned or replaced.
2. Drain any trapped oil from accumulator if used.
3. Remove and discard liquid- line strainer and filter
drier.
4. After system is reassembled, install liquid and
suction- line R- 410A filter driers.
NOTE: On heat pumps, install suction line drier between
compressor and accumulator.
5. Operate system for 10 hr. Monitor pressure drop
across drier. If pressure drop exceeds 3 psig replace
suction- line and liquid- line filter driers. Be sure to
purge system with dry nitrogen when replacing filter
driers. If suction line driers must be replaced, retest
pressure drop after additional 10 hours (run time).
Continue to monitor pressure drop across suction line
filter drier. After 10 hr of run time, remove suction- line
filter drier and replace liquid- line filter drier. Never
leave suction- line filter drier in system longer than 72
hr (run time).
6. Charge system. (See unit information plate.)
CAUTION
!
UNIT DAMAGE HAZARD
Failure to follow this caution may result in equipment
damage or improper operation.
Only suction line filter driers should be used for
refrigerant and oil clean up. Use of non- approved
products could limit system life and void unit warranty.