5-4
T-294-01
CONDITION
POSSIBLE CAUSE
REMEDY/
REFERENCE
SECTION
5.11 THERMOSTATIC EXPANSION VALVE MALFUNCTION
Low refrigerant charge
6.5/6.7
External equalizer line plugged
Open
Wax, oil or dirt plugging valve or orifice Ice formation at
valve seat
6.25
Low suction pressure with high
superheat
Superheat too high
6.5/6.7
superheat
Power assembly failure
6.25
Loss of element/bulb charge
6.25
Broken capillary
6.25
Foreign material in valve
6.25
Hi h
ti
ith l
Superheat setting too low
6.25
High suction pressure with low
superheat
External equalizer line plugged Ice holding valve open
Open
superheat
Foreign material in valve
6.5/6.6
Liquid slugging in compressor
Pin and seat of expansion valve eroded or held open by
foreign material
6.25
Fluctuating suction pressure
Improper bulb location or installation
6.25
Fluctuating suction pressure
Low superheat setting
6.25
5.12 POWER AUTOTRANSFORMER MALFUNCTION
Circuit breaker (CB-1 or CB-2) tripped
Check
Unit will not start
Power transformer (TRANS) defective
6.21
Unit will not start
Power source not turned ON
Check
460 VAC power plug is not inserted into the receptacle
2.4
5.13 WATER-COOLED CONDENSER OR WATER PRESSURE SWITCH
High discharge pressure
Dirty coil
6.28
High discharge pressure
Noncondensibles
6.28
Condenser fan starts and stops
Water pressure switch (WP) malfunction
Check
Condenser fan starts and stops
Water supply interruption
Check
Downloaded from