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5-4
T-317
CONDITION
POSSIBLE CAUSE
REMEDY/
REFERENCE
SECTION
5.10 NO EVAPORATOR AIR FLOW OR RESTRICTED AIR FLOW
Evaporator coil blocked
Frost on coil
5.6
Dirty coil
6.15
No or partial evaporator air flow
Evaporator fan motor internal protector open
6.16
Evaporator fan motor(s) defective
6.16
Evaporator fan(s) loose or defective
6.16
Evaporator fan contactor defective
Replace
5.11 THERMOSTATIC EXPANSION VALVE MALFUNCTION
Low suction pressure with high
superheat
Low refrigerant charge
6.7.1
External equalizer line plugged
Open
Wax, oil or dirt plugging valve or orifice Ice formation at
valve seat
6.14
Superheat too high
6.7.1
Power assembly failure
6.14
Loss of element/bulb charge
Broken capillary
Foreign material in valve
High suction pressure with low
superheat
Superheat setting too low
6.14
External equalizer line plugged Ice holding valve open
Open
Foreign material in valve
6.14
Liquid slugging in compressor
Pin and seat of expansion valve eroded or held open by
foreign material
6.14
Fluctuating suction pressure
Improper bulb location or installation
Low superheat setting
5.12 AUTOTRANSFORMER MALFUNCTION
Unit will not start
Circuit breaker (CB-1 or CB-2) tripped
Check
Autotransformer defective
6.19
Power source not turned ON
Check
460 VAC power plug is not inserted into the receptacle
4.2.2
5.13 WATER-COOLED CONDENSER OR WATER PRESSURE SWITCH
High discharge pressure
Dirty coil
6.12
Noncondensibles
Condenser fan starts and stops
Water pressure switch malfunction
Check
Water supply interruption
Check