Section 6

TROUBLESHOOTING

6.1Unit Will Not Start Or Starts Then Stops

Condition

Possible Cause

Remedy/Refer­ence Section

No power to unit

External power source OFF

Turn On

Start−Stop switch OFF or defective

Check

Circuit breaker tripped or OFF

Check

Loss of control power

Circuit breaker OFF or defective

Check

Control transformer defective

Check

Fuse (F3A/F3B) blown

Check

Start−Stop switch OFF or defective

Check

Component(s) not operating

Evaporator fan motor internal protector open

Section 7.12

Gas Cooler fan motor internal protector open

Section 7.9

Compressor internal protector open

Section 7.3

High pressure switch open

Section 5.7

Heat termination thermostat open

Replace

Malfunction of current sensor

Replace

6.2Unit Operates Long Or Continuously In Cooling

Condition

Possible Cause

Remedy/Refer­ence Section

Container

Hot load

Normal

Defective box insulation or air leak

Repair

Refrigeration system

Shortage of refrigerant

Section 7.2.6

Evaporator coil covered with ice

Section 6.6

Evaporator coil plugged with debris

Section 7.11

Air bypass around evaporator coil

Check

Controller set too low

Reset

Dirty coil

Section 7.8

Current limit (function code Cd32) set to wrong value

Section 4.4.3

Economizer solenoid valve malfunction

Section 7.15

Electronic expansion valve

Replace

6.3Unit Runs But Has Insufficient Cooling

Condition

Possible Cause

Remedy/Refer­ence Section

Refrigeration system

Abnormal pressures

Section 6.7

Abnormal temperatures

Section 6.13

Abnormal currents

Section 6.14

Controller malfunction

Section 6.9

Evaporator fan or motor defective

Section 7.12

Electronic expansion valve

Replace

6.4Unit Will Not Heat Or Has Insufficient Heating

Condition

Possible Cause

Remedy/Refer­ence Section

No operation of any kind

Start−Stop switch OFF or defective

Check

Circuit breaker OFF or defective

Check

External power source OFF

ON

No control power

Circuit breaker or fuse defective

Replace

Control Transformer defective

Replace

Evaporator fan internal motor protector open

Section 7.12

Heat relay defective

Check

Heater termination thermostat open

Section 7.11

Unit will not heat or has insufficient heat

Heater(s) defective

Section 7.11

Heater contactor or coil defective

Replace

Evaporator fan motor(s) defective

Section 7.11/Section 7.12

Evaporator fan motor contactor defective

Replace

Controller malfunction

Section 6.9

Defective wiring

Replace

Loose terminal connections

Tighten

Low line voltage

Section 3.4

6.5Unit Will Not Terminate Heating

Condition

Possible Cause

Remedy/Refer­ence Section

Unit fails to stop heating

Controller improperly set

Reset

Controller malfunction

Section 6.9

Heater termination thermostat remains closed along with the heat relay

Section 7.11

6.6Unit Will Not Defrost Properly

Condition

Possible Cause

Remedy/Refer­ence Section

Will not initiate defrost automati­cally

Defrost timer malfunction (Cd27)

Table 4–6

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

Keypad is defective

Replace

Defrost temperature sensor open

Replace

Initiates but relay (DR) drops out Low line voltage

Section 3.4

Initiates but does not defrost

Heater contactor or coil defective

Replace

Heater(s) burned out

Section 7.11

6.7Abnormal Pressures

Condition

Possible Cause

Remedy/Refer­ence Section

High discharge pressure

Gas Cooler coil dirty

Section 7.8

Gas Cooler fan rotating backwards

Section 7.9

Gas Cooler fan inoperative

Section 7.9

Refrigerant overcharge or non-condensibles

Section 7.2.6

High Pressure Expansion Valve (HPXV) control malfunction

Replace

Low suction pressure

Incorrect software and/or controller configuration

Check

Failed suction pressure transducer (SPT)

Replace

No evaporator air flow or restricted air flow

Section 7.11

EEV control malfunction

Replace

6.8Abnormal Noise Or Vibrations

Condition

Possible Cause

Remedy/Refer­ence Section

Compressor

Loose mounting bolts

Tighten/Replace

Liquid slugging

Section 7.14

Gas Cooler or Evaporator Fan

Bent, loose or striking venturi

Check

Worn motor bearings

Section 7.9/Sec­tion 7.12

Bent motor shaft

Section 7.9/Sec­tion 7.12

6.9Microprocessor Malfunction

Condition

Possible Cause

Remedy/Refer­ence Section

Will not control

Incorrect software and/or controller configuration

Check

Defective sensor

Section 7.20

Defective wiring

Check

Low refrigerant charge

Section 7.2.6

6.10No Evaporator Air Flow Or Restricted Air Flow

Condition

Possible Cause

Remedy/Refer­ence Section

Evaporator coil blocked

Frost on coil

Section 6.6

Dirty coil

Section 7.11

No or partial evaporator air flow

Evaporator fan motor internal protector open

Section 7.12

Evaporator fan motor(s) defective

Section 7.12

Evaporator fan(s) loose or defective

Section 7.12

Evaporator fan contactor defective

Replace

6.11Electronic Expansion Valve Malfunction

Condition

Possible Cause

Remedy/Refer­ence Section

Low suction pressure

Incorrect software and/or controller configuration

Check

Failed suction pressure transducer (SPT)

Replace

No evaporator air flow or restricted air flow

Section 7.11

Excessive frost on evaporator coil

Section 6.6

EEV control malfunction

Section 7.14

Loose or insufficiently clamped sensor (ETS)

Replace

High suction pressure with low su­perheat

Foreign material in valve

Section 6.11

Failed suction pressure transducer (SPT)

Replace

EEV control malfunction

Replace

Liquid slugging in compressor

Failed suction pressure transducer (SPT)

Replace

Failed EEV

Replace

6.12High Pressure Expansion Valve Malfunction

Condition

Possible Cause

Remedy/Refer­ence Section

High discharge pressure

HPXV coil loose, not fully engaged

Section 7.14.1

Incorrect software and/or controller configuration

Check

Failed discharge pressure transducer (DPT)

Replace

Filter drier restriction

Section 7.10

Loose or insufficiently clamped sensor (GCTS)

Check

Gas cooler coil dirty

Section 7.8

Gas cooler fan rotating backwards

Section 7.9

Gas cooler fan inoperative

Section 7.9

HPXV control malfunction

Replace

Failed HPXV

Replace

6.13Abnormal Temperatures

Condition

Possible Cause

Remedy/Refer­ence Section

High discharge temperature

Gas cooler coil dirty

Section 7.8

Gas cooler fan rotating backwards

Section 7.9

Gas cooler fan inoperative

Section 7.9

Refrigerant overcharge or non-condensibles

Section 7.2.6

Electronic expansion valve (EEV) control malfunction

Replace

Failed suction pressure transducer (SPT)

Replace

Discharge temperature sensor drifting high

Replace

Loose or insufficiently clamped sensor

Replace

ESV coil not fully engaged

Section 7.15.2

ESV or ESV coil malfunction

Replace

6.14Abnormal Currents

Condition

Possible Cause

Remedy/Refer­ence Section

Unit reads abnormal currents

Current sensor wiring

Check

Component is defective

Check current draw/Replace as needed