Carrier Streamline Scroll 69NT20-531-300 - Manual (Page 63)

5-4 T-309
CONDITION POSSIBLE CAUSE
REMEDY/
REFERENCE
SECTION
5.9 CONTROLLER MALFUNCTION
Defective Sensor 6.22
Defective wiring Check
Will not control Fuse (F1, F2, F3) blown Replace Will not control
Stepper motor suction modulation valve circuit malfunction 6.20
Low refrigerant charge
6.7
5.10 NO EVAPORATOR AIR FLOW OR RESTRICTED AIR FLOW
Evaporator coil blocked
Frost on coil 5.6
Evaporator coil blocked
Dirty coil 6.15
Evaporator fan motor internal protector open 6.17
No or partial evaporator air flow
Evaporator fan motor(s) defective 6.17
No or partial evaporator air flow
Evaporator fan(s) loose or defective 6.17
Evaporator fan contactor defective Replace
5.11 THERMOSTATIC EXPANSION VALVE MALFUNCTION
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
Low suction pressure with high
s perheat
Superheat not correct 6.7.1
superheat
Power assembly failure
Loss of element/bulb charge
6 14
Broken capillary
6.14
Foreign material in valve
Hi h i i h l
Superheat setting too low 6.14
High suction pressure with low
superheat
External equalizer line plugged Ice holding valve open Open
superheat
Foreign material in valve 6.14
Liquid slugging in compressor
Pin and seat of expansion valve eroded or held open by for-
eign material
6 14
Fluctuating suction pressure
Improper bulb location or installation
6.14
Fluctuating suction pressure
Low superheat setting
5.12 AUTOTRANSFORMER MALFUNCTION
Unit will not start
Circuit breaker (CB-1 or CB-2) tripped Check
Unit will not start
Power source not turned ON Check
5.13 WATER-COOLED CONDENSER OR WATER PRESSURE SWITCH
Condenser fan starts and stops
Water pressure switch malfunction Check
Condenser fan starts and stops
Water supply interruption Check