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DIAGNOSTICS
Service Analyzer Charts
COMPRESSOR OVERHEATING (cont.)
SYMPTOM POSSIBLE CAUSE CHECK OR REMEDIES
Short cycling of
compressor (cont�)
Low charge Check system charge�
Low evaporator airow Dirty coil
Dirty lter
Duct too small or restricted
Faulty run capacitor Replace�
Faulty internal overload Replace compressor�
Faulty Compressor
Valves
Fast equalization/Low pressure dierence Replace compressor and examine system to
locate reason�
ELECTRICAL
SYMPTOM POSSIBLE CAUSE CHECK OR REMEDIES
Voltage present on
load side of com-
pressor contactor
and compressor
won't run
Compressor start components Check start capacitor�
Check potential relay�
Run capacitor Check with ohmmeter
Internal overload Allow time to reset�
Compressor windings Check for correct ohms�
Voltage present on
line side of com-
pressor contactor
only
Thermostat Check for control voltage to contactor coil�
Compressor control circuit High-pressure switch
Low-pressure switch
Ambient thermostat
Solid-state protection control or internal thermal sensors
Compressor timed o/on control or interlock
No voltage on line
side of compressor
contactor
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
Single Phasing (3 phase) Check incoming power and fusing�
FLOODED STARTS
SYMPTOM POSSIBLE CAUSE CHECK OR REMEDIES
Liquid in the com-
pressor shell
Faulty or missing crankcase heater Replace crankcase heater�
Too much liquid in
system
Incorrect piping Check piping guidelines�
Overcharge Check and adjust charge�
Diagnostics