Non-Condensables - Daikin ComfortNet DX7TC Service Instructions Manual

SERVICING
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.
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 first
removing the refrigerant charge, replacing and/or installing
liquid line drier, evacuating and recharging.
CHECKING COMPRESSOR EFFICIENCY
The reason for compressor inefficiency is broken or damaged
scroll flanks on Scroll compressors, reducing the ability of the
compressor to pump refrigerant vapor. The condition of the
scroll flanks is checked in the following 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. Low temperature difference across coil.
D. Low amp draw at compressor.
And the charge is correct. The compressor is faulty –
replace the compressor.
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