Evaporator Air Flow Or Restricted Air Flow; Thermostatic Expansion Valve Malfunction; Autotransformer Malfunction; Water-Cooled Condenser Or Water Pressure Switch - Carrier 69NT40-511-310 Operation & Service Manual

CONDITION
5.10 NO EVAPORATOR AIR FLOW OR RESTRICTED AIR FLOW
Evaporator coil blocked Evaporator coil blocked
No or partial evaporator air flow No or partial evaporator air flow

5.11 THERMOSTATIC EXPANSION VALVE MALFUNCTION

Low suction pressure with high
superheat superheat
High suction pressure with low Hi h i
superheat superheat
Liquid slugging in compressor
Fluctuating suction pressure Fluctuating suction pressure

5.12 AUTOTRANSFORMER MALFUNCTION

Unit will not start Unit will not start

5.13 WATER-COOLED CONDENSER OR WATER PRESSURE SWITCH

High discharge pressure High discharge pressure
Condenser fan starts and stops Condenser fan starts and stops
T-296
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Frost on coil
Dirty coil
Evaporator fan motor internal protector open
Evaporator fan motor(s) defective
Evaporator fan(s) loose or defective
Evaporator fan contactor defective
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
Superheat setting too low
i h l
External equalizer line plugged Ice holding valve open
Foreign material in valve
Pin and seat of expansion valve eroded or held open by
foreign material
Improper bulb location or installation
Low superheat setting
Circuit breaker (CB-1 or CB-2) tripped
Autotransformer defective
Power source not turned ON
460 VAC power plug is not inserted into the receptacle
Dirty coil
Noncondensibles
Water pressure switch malfunction
Water supply interruption
search engine
POSSIBLE CAUSE
5-4
REMEDY/
REFERENCE
SECTION
5.6
6.15
6.16
6.16
6.16
Replace
6.7.1
Open
6.14
6.7.1
6.14 6 14
6.14
Open
6.14
6.14 6 1
Check
6.19
Check
4.2.2
6.12 6 12
Check
Check