Carrier 69NT40-511-199 - Manual (Page 94)

5-4 T-268-07
CONDITION POSSIBLE CAUSE
REMEDY/
REFERENCE
SECTION
5.11 THERMOSTATIC EXPANSION VALVE MALFUNCTION
Low suction pressure with high
superheat
Low refrigerant charge
External equalizer line plugged
Wax, oil or dirt plugging valve or orifice Ice formation at
valve seat
Superheat too high
Power assembly failure
Loss of element/bulb charge
Broken capillary
Foreign material in valve
6.4/6.6
Open
6.26
6.4/6.6
6.26.c
6.26
6.26
6.26
High suction pressure with low
superheat
Superheat setting too low
External equalizer line plugged Ice holding valve open
Foreign material in valve
6.26.c
Open
6.4/6.5 6.26
Liquid slugging in compressor
Pin and seat of expansion valve eroded or held open by
foreign material
6.26
Fluctuating suction pressure
Improper bulb location or installation
Low superheat setting
6.26
6.26.c
5.12 POWER AUTOTRANSFORMER MALFUNCTION
Unit will not start
Circuit breaker (CB-1 or CB-2) tripped
Power transformer defective
Power source not turned ON
460 VAC power plug is not inserted into the receptacle
Check
6.22
Check
2.4
5.13 WATER-COOLED CONDENSER OR WATER PRESSURE SWITCH
High discharge pressure
Dirty coil
Noncondensibles
6.28
Condenser fan starts and stops
Water pressure switch malfunction
Water supply interruption
Check