40
Table 18: Service Analyzer Chart (cont.)
COMPRESSOR OVERHEATING – HIGH DISCHARGE TEMP (cont.)
SYMPTOM POSSIBLE CAUSE REMEDY
Short cycling of
compressor (cont.)
Low charge Check system charge.
Low evaporator airow
Dirty coil
Dirty lter
Duct too small or restricted
Faulty internal overload Replace compressor.
ELECTRICAL
SYMPTOM POSSIBLE CAUSE REMEDY
Voltage present on
load side of inverter
and compressor
won't run
Communication failure from UODC to inverter.
Check communication harness connectors and wire
continuity.
Compressor windings Check for correct ohms.
187 – 252VAC
present at input to
inverter
Thermostat Check for control voltage to contactor coil.
Compressor control circuit
High-pressure switch
Low-pressure cut-out
Ambient thermostat
Stater heat is active
Compressor timed off/on control or interlock
No voltage at input
to inverter
Blown fuses or tripped circuit breaker Check for short in wiring or unit.
Improper wiring Recheck wiring diagram.
Improper voltage
High voltage
Wrong unit
Power supply problem
Low voltage
Wrong unit
Power supply problem
Wiring undersized
Loose connections
FLOODED STARTS
SYMPTOM POSSIBLE CAUSE REMEDY
Liquid in the com-
pressor shell
Faulty stator heat circuit (single leg output
to compressor)
Check inverter for single leg output power and correct wiring.
Too much liquid in
system
Incorrect piping Check piping guidelines.
Overcharge Check and adjust charge.
CONTAMINATION
SYMPTOM POSSIBLE CAUSE REMEDY
Moisture Poor evacuation on installation or during service
In each case, the cure is the same. Recover refrigerant,
ush system. Add lter driver, evacuate, and recharge.
High head pressure Noncondensibles air
Unusual head and
suction pressure
readings
Wrong refrigerant or mixed refrigerants
Foreign matter –
copper lings
Copper tubing cuttings
Copper oxide
Dirty copper piping or nitrogen not used when
brazing
Welding scale Nitrogen not used during brazing
Soldering ux Adding ux before seating copper partway
Excess soft solder Wrong solder material
Diagnostics
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