Condensing Unit & Heat Pump R410A Service Manual
122
S-115 COMPRESSOR BURNOUT
When a compressor burns out, high temperature develops
causing the refrigerant, oil and motor insulaon to decompose
forming acids and sludge.
If a compressor is suspected of being burned-out, aach a
refrigerant hose to the liquid line dill valve and properly remove
and dispose of the refrigerant.
NOTICE
Violation of EPA regulations may result in fines
or other penalties.
Now determine if a burn out has actually occurred. Conrm by
analyzing an oil sample using a Sporlan Acid Test Kit, AK-3 or its
equivalent.
Remove the compressor and obtain an oil sample from the
sucon stub. If the oil is not acidic, either a burnout has not
occurred or the burnout is so mild that a complete clean-up is
not necessary.
If acid level is unacceptable, the system must be cleaned by
using the clean-up drier method.
Do not allow the sludge or oil to contact the skin.
Severe burns may result.
CAUTION
NOTE: The Flushing Method using R-11 refrigerant is no longer
approved by Amana® Brand Heang-Cooling.
The POE oils used with R410A refrigerant is an excellent solvent.
In the case of a burnout, the POE oils will remove any burnout
residue le in the system. If not captured by the refrigerant
lter, they will collect in the compressor or other system
components, causing a failure of the replacement compressor
and/or spread contaminants throughout the system, damaging
addional components.
Install a eld supplied sucon line drier. This drier should be
installed as close to the compressor sucon ng as possible.
The lter must be accessible and be rechecked for pressure drop
aer the system has operated for a me. It may be necessary to
use new tubing and form as required.
NOTE: At least twelve (12) inches of the sucon line
immediately out of the compressor stub must be discarded due
to burned residue and contaminates.
SERVICING
S-113 OVERCHARGE OF REFRIGERANT
An overcharge of refrigerant is normally indicated by an
excessively high head pressure.
An evaporator coil, using an expansion valve metering device,
will basically modulate and control a ooded evaporator and
prevent liquid return to the compressor.
An evaporator coil, using a capillary tube metering device, could
allow refrigerant to return to the compressor under extreme
overcharge condions. Also with a capillary tube metering
device, extreme cases of insucient indoor air can cause icing of
the indoor coil and liquid return to the compressor, but the head
pressure would be lower.
There are other causes for high head pressure which may be
found in the “Service Problem Analysis Guide.”
If other causes check out normal, an overcharge or a system
containing non-condensables would be indicated.
If this system is observed:
1. Start the system.
2. Remove and capture small quanes of gas from the sucon
line dill valve unl the head pressure is reduced to normal.
3. Observe the system while running a cooling performance
test. If a shortage of refrigerant is indicated, then the system
contains non-condensables.
S-114 NON-CONDENSABLES
If non-condensables are suspected, shut down the system
and allow the pressures to equalize. Wait at least 15 minutes.
Compare the pressure to the temperature of the coldest
coil since this is where most of the refrigerant will be. If the
pressure indicates a higher temperature than that of the coil
temperature, non-condensables are present.
Non-condensables are removed from the system by rst
removing the refrigerant charge, replacing and/or installing
liquid line drier, evacuang and recharging.
CHECKING COMPRESSOR EFFICIENCY
The reason for compressor ineciency is broken or damaged
scroll anks on Scroll compressors, reducing the ability of the
compressor to pump refrigerant vapor. The condion of the
scroll anks is checked in the following manner.
1. Aach gauges to the high and low side of the system.
2. Start the system and run a “Cooling Performance Test. If the
test shows:
a. Below normal high side pressure.
b. Above normal low side pressure.
c. Low temperature dierence across coil.
d. Low amp draw at compressor.
And the charge is correct. The compressor is faulty – replace
the compressor.