T-349 6–46.9 CONTROLLER MALFUNCTIONWill not controlDefective Sensor 7.23Defective wiring CheckFuse (F1, F2) blown ReplaceStepper motor suction modulation valve circuit malfunction 7.196.10 NO EVAPORATOR AIR FLOW OR RESTRICTED AIR FLOWEvaporator coil blocked Frost on coil 6.6Dirty coil 7.15No or partial evaporator air flowEvaporator fan motor internal protector open 7.16Evaporator fan motor(s) defective 7.16Evaporator fan(s) loose or defective 7.16Evaporator fan contactor defective Replace6.11 THERMOSTATIC EXPANSION VALVE MALFUNCTIONLow suction pressurewith high superheatLow refrigerant charge 7.7.1External equalizer line plugged OpenWax, oil or dirt plugging valve or orifice ice formation at valve seat 7.14Superheat too high 7.7.1Power assembly failure7.14Loss of element/bulb chargeBroken capillaryForeign material in valveHigh suction pressurewith low superheatSuperheat setting too low 7.14External equalizer line plugged ice holding valve open OpenForeign material in valve 7.14Liquid slugging in compressor Pin and seat of expansion valve eroded or held open byforeign material7.14Fluctuating suction pressure Improper bulb location or installationLow superheat setting6.12 AUTOTRANSFORMER MALFUNCTIONUnit will not startCircuit breaker (CB-1 or CB-2) tripped CheckAutotransformer defective 7.21Power source not turned ON Check460 VAC power plug is not inserted into the receptacle 5.2.16.13 WATER-COOLED CONDENSER OR WATER PRESSURE SWITCHHigh discharge pressure Dirty coil 7.12NoncondensiblesCondenser fan starts and stops Water pressure switch malfunction CheckWater supply interruption CheckCONDITION POSSIBLE CAUSEREMEDY/REFERENCESECTION
