GSZH5 Service Manual
100
SERVICING
5. Capture the charge, replace the valve and drier,
evacuate and recharge.
When the system is operating, the liquid line is warm to the
drop will be noticed at the point of restriction. In severe
cases, frost will form at the restriction and extend down the
Discharge and suction pressures will be low, giving the
appearance of an undercharged unit. However, the unit will
have normal to high subcooling.
Locate the restriction, replace the restricted part, replace
drier, evacuate and recharge.
Overcharge Of Refrigerant
An overcharge of refrigerant is normally indicated by an
excessively high head pressure.
An evaporator coil, using an expansion valve metering
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 conditions. Also with a capillary tube
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 quantities of gas from the
suction line dill valve until 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.
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.
removing the refrigerant charge, replacing and/or installing
liquid line drier, evacuating and recharging.
ability of the compressor to pump refrigerant vapor. The
manner.
1. Attach 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.
d. Low amp draw at compressor.
And the charge is correct. The compressor is faulty –
replace the compressor.
Compressor Burnout
When a compressor burns out, high temperature develops
causing the refrigerant, oil and motor insulation to
decompose forming acids and sludge.
If a compressor is suspected of being burned-out, attach
a refrigerant hose to the liquid line dill valve and properly
remove and dispose of the refrigerant.
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
suction 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.
CAUTION
is no longer approved by Amana® Brand Heating-
Cooling.