6_Troubleshooting

Section 6

TROUBLESHOOTING

6.1Unit Will Not Start or Starts Then Stops
Condition	Possible Cause	Remedy / Reference
No power to unit	External power source OFF	Turn on
	Start-Stop switch OFF or defective	Check
	Circuit breaker tripped or OFF	Check
	Autotransformer not connected	5.2.2
Loss of control power	Circuit breaker OFF or defective	Check
	Control transformer defective	Replace
	Fuses (F3A, F3B) blown	Check
	Start-Stop switch OFF or defective	Check
Component(s) Not Operating	Evaporator fan motor internal protector open	7.16
	Condenser fan motor internal protector open	7.11
	Compressor internal protector open	7.8
	High pressure switch open	6.7
	Heat termination thermostat open	Replace
Compressor hums, but does not start	Low line voltage	Check
	Single phasing	Check
	Shorted or grounded motor windings	7.8
	Compressor seized	7.8

6.2Unit Operates Long or Continuously Long in Cooling
Condition	Possible Cause	Remedy / Reference
Container	Hot load (Failure to Pre-cool)	Normal
Container	Defective box insulation or air leak	Repair
Refrigeration System	Shortage of refrigerant	7.7.1
	Evaporator coil covered with ice	6.6
	Evaporator coil plugged with debris	7.15
	Evaporator fan(s) rotating backwards	7.15/7.16
	Defective evaporator fan motor	7.16
	Air bypass around evaporator coil	Check
	Controller set too low	Reset
	Compressor service valves or liquid line shutoff valve partially closed	Open valves completely
	Dirty condenser	7.10
	Compressor worn	7.8
	Current limit (function code Cd32) set to wrong value	4.4.3
	Suction modulation valve malfunction	7.19

6.3Unit Runs But Has Insufficient Cooling
Condition	Possible Cause	Remedy / Reference
Compressor	Compressor valves defective	7.8
Refrigeration System	Abnormal pressures	6.7
	Controller malfunction	6.9
	Evaporator fan or motor defective	7.16
	Suction modulation valve malfunction	7.19
	Condenser Pressure Transducer defective	Check
	Shortage of refrigerant	7.7.1

6.4Unit Will Not Heat or Has Insufficient Heating
Condition	Possible Cause	Remedy / Reference
No operation of any kind	Start-Stop switch OFF or defective	Check
	Circuit breaker OFF or defective	Check
	External power source OFF	Turn ON
No control power	Circuit breaker or fuse defective	Replace
	Control Transformer defective	Replace
	Evaporator fan internal motor protector open	7.16
	Heat relay defective	Check
	Heater termination switch open	7.15
Unit will not heat or has insufficient heat	Heater(s) defective	7.15
	Heater contactor or coil defective	Replace
	Evaporator fan motor(s) defective or rotating backwards	7.15/7.16
	Evaporator fan motor contactor defective	Replace
	Controller malfunction	6.9
	Defective wiring	Replace
	Loose terminal connections	Tighten
	Low line voltage	3.3

6.5Unit Will Not Terminate Heating
Condition	Possible Cause	Remedy / Reference
Unit fails to stop heating	Controller improperly set	Reset
	Controller malfunction	6.9
	Heater termination thermostat remains closed along with the heat relay	7.15

6.6Unit Will Not Defrost Properly
Condition	Possible Cause	Remedy / Reference
Will not initiate defrost automatically	Defrost timer malfunction (Cd27)	Table 4–5
	Loose terminal connections	Tighten
	Defective wiring	Replace
	Defrost temperature sensor defective or heat termination thermostat open	Replace
	Heater contactor or coil defective	Replace
Will not initiate defrost manually	Manual defrost switch defective	Replace
Will not initiate defrost manually	Defrost temperature sensor open	7.24
Initiates but relay (DR) drops out	Low line voltage	3.3
Initiates but does not defrost	Heater contactor or coil defective	Replace
Initiates but does not defrost	Heater(s) burned out	7.15
Frequent defrost	Wet load	Normal

6.7Abnormal Pressures (Cooling)
Condition	Possible Cause	Remedy / Reference
High discharge pressure	Condenser coil dirty	7.10
	Condenser fan rotating backwards	7.11
	Condenser fan inoperative	7.11
	Refrigerant overcharge or noncondensibles	7.7.1
	Discharge pressure regulator valve defective	7.21
	Discharge service valve partially closed	Open
	Suction modulation valve malfunction	7.19
Low suction pressure	Suction service valve partially closed	Open
	Filter-drier partially plugged	7.13
	Low refrigerant charge	7.7.1
	Expansion valve defective	7.14
	No evaporator air flow or restricted air flow	7.15
	Excessive frost on evaporator coil	6.6
	Evaporator fan(s) rotating backwards	7.16.3
	Discharge pressure regulator valve defective	7.21
	Suction modulation valve malfunction	7.19
Suction and discharge pressures tend to equalize when unit is operating	Heat exchanger defective	Replace
	Compressor valves defective	7.8
	Compressor cycling/stopped	Check

6.8Abnormal Noise or Vibrations
Condition	Possible Cause	Remedy / Reference
Compressor	Loose mounting bolts	Tighten
	Worn bearings	7.8
	Worn or broken valves	7.8
	Liquid slugging	7.14
	Insufficient oil	7.8.6
Condenser or Evaporator Fan	Bent, loose or striking venturi	Check
	Worn motor bearings	7.11/7.16
	Bent motor shaft	7.11/7.16

6.9Microprocessor Malfunction
Condition	Possible Cause	Remedy / Reference
Will not control	Defective Sensor	7.24
	Defective wiring	Check
	Fuse (F1, F2) blown	Replace
	Stepper motor suction modulation valve circuit malfunction	7.19

6.10No Evaporator Air Flow or Restricted Air Flow
Condition	Possible Cause	Remedy / Reference
Evaporator coil blocked	Frost on coil	6.6
Evaporator coil blocked	Dirty coil	7.15
No or partial evaporator air flow	Evaporator fan motor internal protector open	7.16
	Evaporator fan motor(s) defective	7.16
	Evaporator fan(s) loose or defective	7.16
	Evaporator fan contactor defective	Replace

6.11EAutoFresh Not Operating
Condition	Possible Cause	Remedy / Reference
Vent not opening	Unit not Configured for eAutoFresh Operation	No action
	Cd43 in Off mode	5.4.2
	Wiring disconnected	Check wiring
	Stepper drive defective	7.26.2
	Stepper motor defective	7.26.2
	Unit operating in frozen mode	5.4.3
Gas Limit mode unavailable	Check CO₂ sensor	5.4.3
	Wiring disconnected	Check wiring
	Unit operating in frozen mode	5.4.3
Unable to calibrate CO₂sensor	Enter Key not held for sufficient length of time	5.4.3
	CO₂ outside of acceptable levels	Check
	Check CO₂ sensor	5.4.3
Cd44 displays -----	Unit not Configured for eAutoFresh Operation	No action
Cd44 displays -----	Check CO₂ sensor	5.4.3

6.12Thermostatic Expansion Valve Malfunction
Condition	Possible Cause	Remedy / Reference
Low suction pressure with high superheat	Low refrigerant charge	7.7.1
	External equalizer line plugged	Open
	Wax, oil or dirt plugging valve or orifice ice formation at valve seat	7.14
	Superheat too high	7.7.1
	Power assembly failure	7.14
	Loss of element/bulb charge	7.14
	Broken capillary	7.14
	Foreign material in valve	7.14
High suction pressure with low superheat	Superheat setting too low	7.14
	External equalizer line plugged ice holding valve open	Open
	Foreign material in valve	7.14
Liquid slugging in compressor	Pin and seat of expansion valve eroded or held open by foreign material	7.14
Fluctuating suction pressure	Improper bulb location or installation	7.14
Fluctuating suction pressure	Low superheat setting	7.14

6.13Autotransformer Malfunction
Condition	Possible Cause	Remedy / Reference
Unit will not start	Circuit breaker (CB1 or CB2) tripped	Check
	Autotransformer defective	7.22
	Power source not turned ON	Check
	460 VAC power plug is not inserted into the receptacle	5.2.2

6.14Water-Cooled Condenser (WCC) or Water Pressure Switch (WPS)
Condition	Possible Cause	Remedy / Reference
High discharge pressure	Dirty coil	7.12
	Noncondensibles	7.12
Condenser fan starts and stops	Water pressure switch malfunction	Check
	Water supply interruption	Check