Rheem Air Conditioner Error Codes



Descriptions of the ICC diagnostic codes are provided below:

Rheem AC Error Codes and Troubleshooting
Rheem AC Error Codes and Troubleshooting
Display CodesDiagnostic DescriptionPossible Cause
0- StandbyNo command for unit operationNormal operation
c - First Stage CoolingUnit has received a command for first stage coolingNormal operation
c FlashingAnti-short cycle timer (3 minutes) or Minimum run timer (30 seconds) active
  • The unit has received a command for first stage cooling during an active anti-short cycle timer or minimum run timer.

  • Wait until unit timer has expired or press the TEST button to defeat short cycle delay.
  • C - Second Stage CoolingUnit has received a command for second stage coolingNormal operation
    C FlashingAnti-short cycle timer (3 minutes) or Minimum run timer (30 seconds) active
  • The unit has received a command for second stage cooling during an active anti-short cycle timer or minimum run timer.

  • Wait unit timer has expired or press the TEST button to defeat short cycle delay.
  • h - First Stage Heat PumpUnit has received a command for first stage heat pumpNormal operation
    h FlashingAnti-short cycle timer (3 minutes) or Minimum run timer (30 seconds) action
  • The unit has received a command for first stage heat pump during an active anti-short cycle timer or minimum run time

  • Wait unit timer has expired or press the TEST button to defeat short cycle delay
  • H - Second Stage Heat PumUnit has received a command for second stage heat pumpNormal operation
    H FlashingAnti-short cycle timer (3 minutes) or Minimum run timer (30 seconds) active
  • The unit has received a command for second stage heat pump during an active anti-short cycle timer or minimum run timer.

  • Wait unit timer has expired or press the TEST button to defeat short cycle delay
  • d - Defrost ActiveThe unit is undergoing a defrost cycleNormal operation
    t - Test ModTest ModThe ICC is in TEST mode
    P - Protector TripA command for compressor operation is present but no current is measured to the compressorMotor protector open
    01 - Long Run Time (Compressor)The compressor has continuously run for more than 18 hours in the cooling mode.
  • Low refrigerant charge

  • Air ducts have substantial leakage

  • Dirty indoor air filter

  • Dirty outdoor coil
  • 02 - High PressureCompressor limit has opened four (4) times within a call for operation
  • Outdoor coil is dirty (cooling mode)

  • Outdoor fan is not running (cooling mode)

  • Dirty indoor coil or filter (heating mode)

  • Indoor blower is not running (heating mode)

  • Liquid line restriction

  • Excessive refrigerant charge
  • 03 - Short CyclingICC detects the run time for the past four (4) compressor or cycles is less than three (3) minutes each
  • Check thermostat wire connection

  • Check thermostat location in zone
  • L4 - Locked RotorThe ICC detects four (4) consecutive protector trips have occurred and the average run time for each trip is less than 15 seconds
  • Bad run capacitor

  • Low line voltage

  • Excessive refrigerant in compressor

  • Seized bearings in compressor
  • 05 - Open circuit (Compressor Will not Run)The ICC has had a protector trip for longer than 4 hours
  • Check for damaged, miswired, or wrong run capacitor

  • Check for broken Wires, loose connectors, or miswired compressor

  • Check compressor windings for continuity

  • Check for open compressor internal protector
  • 06 - Compressor Open Start CircuitThe ICC detects current in the Run circuit but not in the Start circuit of the compressor
  • Check for damaged, miswired, or wrong run capacitor

  • Check for broken Wires, loose connectors, or miswired compressor

  • Check compressor windings for continuity
  • L6 - Compressor Open Start CircuitThe ICC detects current in the Run circuit but not in the Start circuit of the compressor four (4) times in one compressor call
  • Check for damaged, miswired, or wrong run capacitor

  • Check for broken Wires, loose connectors, or miswired compressor

  • Check compressor windings for continuity
  • 07 - Compressor Open Run CircuitThe ICC detects current in the Start circuit but not in the Run circuit of the compressor
  • Check for damaged, miswired, or wrong run capacitor

  • Check for broken Wires, loose connectors, or miswired compressor

  • Check compressor windings for continuity
  • L7 - Compressor Open Run CircuitThe ICC detects current in the Start circuit but not in the Run circuit of the compressor four (4) times in one compressor call
  • Check for damaged, miswired, or wrong run capacitor

  • Check for broken Wires, loose connectors, or miswired compressor

  • Check compressor windings for continuity
  • 09 - Low Secondary VoltsThe secondary voltage at R and C is below 18VAC
  • Control transformer overloaded

  • Low line voltage
  • 21 - Low Pressure Control OpenThe ICC detects the LPC is open. Note: The low pressure control is ignored for the first 90 seconds of compressor operation
  • Unit has low refrigerant charge

  • Indoor coil is frozen (cooling mode)

  • Dirty indoor coil or filter (cooling mode)

  • Indoor blower is not running (cooling mode)

  • Outdoor coil is frozen (heating mode)

  • Expansion valve is not operating correctly
  • L21 FlashingActive Protection, Low Pressure Control TripLPC has opened 3 times in the same cooling operation, the ICC has locked out the compressor to protect it. ICC alternately flashes L and 21.
    27Low Line Voltage or No Line Voltage Fault
  • Check incoming line voltage to the disconnect and unit

  • Check wiring connections
  • 28High Line Voltage FaultCheck line voltage
    29High Pressure Control Open. The ICC detects the HPC is open
  • Outdoor coil is dirty (cooling mode)

  • Outdoor fan is not running (cooling mode)

  • Dirty indoor coil or filter (heating mode)

  • Indoor blower is not running (heating mode)

  • Liquid line restriction

  • Excessive refrigerant charge
  • L29 Flashing - Active ProtectionHigh Pressure Control TripLPC has opened 3 times in the same cooling operation, the ICC has locked out the compressor to protect it. ICC alternately flashes L and 29
    30 - Fuse OpenThe ICC detects the on—board fuse is open
  • The 3—amp fuse on the ICC is open.

  • Low voltage Wiring at R and C is damaged or miswired.
  • 80 - Low Air FlowThe ICC detects that the indoor unit is not providing the minimum airflow requirements.Misappliedwrong indoor air mover - replace With properly sized unit.
    83 - Condenser Coil Temperature FaultThe sensor detects an abnormally low or high coil temperature
  • Replace the sensor

  • Check sensor is installed correctly on control
  • 84 - Outdoor Ambient Temperature FaultThe sensor detects an abnormally low or high outdoor ambient temperature
  • Check unit placement - If the outdoor unit is in a high temperature area, wait until the ambient temperature drops and check sensor reading.

  • Replace the sensor.

  • Check sensor is installed correctly on control
  • 93 - Internal Control FaultThe control is not functioning properly.
  • Check control for proper system Operation.

  • Replace control
  • d1N0 Shared DataReplace memory card With correct system information.
    d3 - Airflow CFM MismatchThe indoor air mover (air handler/furnace) cannot supply the required airflow for proper system operationMisappliedwrong indoor air mover-replace With properly sized air handler/furnace.
    d4 - (Device) Memory Card Invalid for DeviceThe data in the memory card inserted into the control board does not match the data in the control.
  • Check memory card to ensure it matches device

  • Check if memory card is present
  • d8 - Old Shared DataSystem data is obsoleteIf system Will not operate, order new memory card to update system information.

    Rheem AC ICC Diagnostic Codes

    Descriptions of the ICC diagnostic codes are provided below: NOTE: Codes must be read from correct side to avoid an error in reading codes.

    Rheem AC ICC Diagnostic Codes
    Rheem AC ICC Diagnostic Codes

    Electrical Checks Flowchart




    Thermostat Call For Cooling, No Cooling

    Rheem AC Electrical Checks Flowchart
    Rheem AC Electrical Checks Flowchart

    Troubleshooting

    Rheem AC Troubleshooting
    Rheem AC Troubleshooting

    Disconnect all power to unit before servicing. Contactor may break only one side. Failure to shut off power can cause electrical shock resulting in personal injury or death.

    SYMPTOM: Unit will not run

    POSSIBLE CAUSE:

    1. Power off or loose electrical connection
    2. Thermostat out of calibration – set too high
    3. Defective control board
    4. Blown fuses/tripped breaker
    5. Transformer defective
    6. High-pressure control open/Low-pressure control open
    7. Miswiring of communications

    REMEDY:

    1. Check for correct voltage at line voltage connections in condensing unit.
    2. Reset.
    3. Check control board diagnostic codes.
    4. Replace fuses/reset breaker.
    5. Check wiring. Replace transformer.
    6. Reset. Also see high head pressure remedy. The highpressure control opens at 610 PSIG.
    7. Check communication wiring

    SYMPTOM: Outdoor fan runs, compressor doesn’t

    POSSIBLE CAUSE:

    1. Run or start capacitor defective
    2. Contactor defective
    3. Loose connection
    4. Compressor stuck, grounded or open motor winding, open internal overload.
    5. Low-voltage condition

    REMEDY:

    1. Replace.
    2. Replace.
    3. Check for correct voltage at compressor. Check and tighten all connections.
    4. Wait at least 3 hours for overload to reset. If still open, replace the compressor.
    5. Add start kit components.

    SYMPTOM: Insufficient cooling

    POSSIBLE CAUSE:

    1. Improperly sized unit
    2. Improper indoor airflow
    3. Incorrect refrigerant charge
    4. Air, noncondensibles, or moisture in system
    5. Bad ID TXV

    REMEDY:




    1. Recalculate load.
    2. Check. Should be approximately 400 CFM per ton.
    3. Charge per procedure attached to unit service panel.
    4. Recover refrigerant. Evacuate and recharge. Add filter drier.
    5. Replace TXV

    SYMPTOM: Compressor short cycles

    POSSIBLE CAUSE:

    1. Incorrect voltage
    2. Defective overload protector
    3. Refrigerant undercharge

    REMEDY:

    1. At compressor terminals, voltage must be ± 10% of nameplate marking when unit is operating.
    2. Replace. Check for correct voltage.
    3. Add refrigerant.

    SYMPTOM: Registers sweat

    POSSIBLE CAUSE: Low indoor airflow

    REMEDY: Increase speed of blower or reduce restriction. Replace air filter

    SYMPTOM:  High head, low vapor pressures

    POSSIBLE CAUSE:

    1. Restriction in liquid line, expansion device, or filter drier
    2. Bad TXV

    REMEDY:

    1. Remove or replace defective component.
    2. Replace TXV

    SYMPTOM:  High head, high or normal vapor pressure – Cooling mode

    POSSIBLE CAUSE:

    1. Dirty outdoor coil
    2. Refrigerant overcharge
    3. Outdoor fan not running
    4. Air or noncondensibles in system

    REMEDY:

    1. Clean coil.
    2. Correct system charge.
    3. Repair or replace.
    4. Recover refrigerant. Evacuate and recharge

    SYMPTOM:  Low head, high vapor pressures

    POSSIBLE CAUSE:

    1. Bad TXV
    2. Bad compressor

    REMEDY:



    1. Replace TXV.
    2. Replace compressor

    SYMPTOM:  Low vapor, cool compressor, iced indoor coil

    POSSIBLE CAUSE:

    1. Low indoor airflow
    2. Operating below 65°F outdoors
    3. Moisture in system
    4. Closed ID circuit

    REMEDY:

    1. Increase speed of blower or reduce restriction. Replace air filter.
    2. Add Low Ambient Kit.
    3. Recover refrigerant. Evacuate and recharge. Add filter drier.
    4. Repair or replace ID coil

    SYMPTOM: High vapor pressure

    POSSIBLE CAUSE:

    1. Excessive load
    2. Defective compressor

    REMEDY:

    1. Recheck load calculation.
    2. Replace.

    SYMPTOM: Fluctuating head and vapor pressures

    POSSIBLE CAUSE:

    1. TXV hunting
    2. Air or noncondensibles in system

    REMEDY:

    1. Check TXV bulb clamp. Check air distribution on coil. Replace TXV.
    2. Recover refrigerant. Evacuate and recharge.

    SYMPTOM: Gurgle or pulsing noise at expansion device or liquid line

    POSSIBLE CAUSE: Air or noncondensibles in system

    REMEDY: Recover refrigerant. Evacuate and recharge.

    Service Analyzer Charts

    Rheem AC Service Analyzer Charts
    Rheem AC Service Analyzer Charts

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