heatcraft-refrigeration-p h-im-79d User Manual

   PROBLEM

Step ACTION ITEM

IF OK

IF NOT OK

1.

Check Primary Power Supply Disconnect

1.  Check fuses and circuit breakers

2.

Check Voltage to Evaporator Transformer

Go to

2.  Check field wiring for breaks

LED is not lit.

3.

Check Transformer Secondary Output Volts

next step

3.  Replace if necessary

4.

Check Voltage at Control Board (24V and C)

4.  Check factory wiring and connections

5.

Replace Control Board

1.

Check Compressor internal overloads

1.  Wait for reset

2.

Check Control Power to Condensing Unit

2.  Check transformer voltage (secondary and

LED shows 

, but

(24 Volts across “COMP” and “C” at board)

Go to

     primary) and wiring of 208V power taps.

compressor will not run.

3.

Check Compressor Contactor Coil Voltage

next step

3.  Check internal condensing unit wiring

4.

Check Compressor Contactor “pulled in”

4.  Replace as needed

  E1

  Room Sensor

Check Sensor and Board Connection

Replace as needed

E2

  Defrost Sensor

Check Sensor and Board Connection

Replace as needed

  E3

  Suction Sensor

Check Sensor and Board Connection

Replace as needed

  E4

  Suction Transducer

Check Transducer and Board Connection

Replace as needed

  

E5

  Outdoor Sensor

Check Sensor, wiring and Board Connection

Replace or remove

1.

Check Refrigerant Type

1.  Compare board setpoint and refrigerant

2.

Check coil for ice

2.  Defrost coil and check defrost cycle
     settings/setpoints, defrost sensor and
     heater amps.

  Low Superheat

3.

Check Control Board step position from board LED

3.  Replace board if EEV steps not at 2.

4.

Check Electric Expansion Valve Closure

Go to

4.  Pumpdown system see if LPS opens or if it

        (0

°

F for 2 minutes)

next step

     times out (EEV is bad or LPS is set
     incorrectly, if times out) – See Pumpdown.

5.

Compressor Not Operating

5.  Check overloads and contactor.

6.

Check Suction Temperature Sensor

6.  Compare board sensor reading against
     actual suction line temperature.

7.

Check Suction Pressure Transducer

7.  Compare pressure reading against gauges.

°

°