Lennox Error Codes

Communication error between Hydro unit / Hydro unit HT and outdoor unit (When Hydro unit / Hydro unit HT is having trouble with…

Communication error on outdoor unit (When outdoor unit is having trouble sending data to Hydro unit / Hydro unit HT)

Error of duplicated communication addresses (NASA only)

Communication error on indoor address incompletion

Communication error between Hydro unit / Hydro unit HT and Control Kit (Detection from the Control Kit)

Indoor unit R-32 sensor failure.

Error on room temperature sensor of Hydro unit / Hydro unit HT (Short or Open)

Error on EVA IN sensor of Hydro unit / Hydro unit HT (Short or Open)

Error on EVA OUT sensor of Hydro unit / Hydro unit HT (Short or Open)

3. The evaporator-in sensor is detached.

4. The evaporator-out sensor is detached.

EVA IN and EVA OUT sensor of Hydro unit / Hydro unit HT is detached

Error due to the opened EEV (2nd detection)

2. Error due to the closed EEV (2nd detection)

Error of the second detection of the float switch

Error of the fan in the indoor unit

Error of mixed operation

EEPROM error

EEPROM option error

Error of incompatibility of the indoor unit

Check the water circulating

18. Simultaneous opening of the cooling and heating MSB SOL valves (1st detection)

19. Simultaneous opening of the cooling and heating MSB SOL valves (2nd detection)

Cross wiring error (When power line is connected to communication line of Hydro unit / Hydro unit HT)

Auto pipe pairing setting error; alternateswithindooraddress andSEG3/4statusdata.

Error due to disconnected Thermal Fuse (When the temperature of terminal block is increases)

The number of the installed indoor units that is transmitted via communication after the tracking is different.

Error of 3 minute tracking on the outdoor unit

1. Open or short circuit error of the outdoor-temperature sensor

2. Open or short circuit error of the condenser sensor

5. The condenser mid sensor is detached.

3. Open or short circuit error of the discharge sensor

13. The high pressure sensor is detached.

14. The low pressure sensor is detached.

12. The compressor stops due to freeze detection (6th detection)

17. Compressor shutdown due to the low-pressure-sensor prevention control_1

16. Outdoor sump down_1 prevention control

9. Abnormal high temperature on the air discharged from the outdoor unit (2nd detection)

11. Error of detection of a reverse phase

15. Compression ratio error of the outdoor unit

8. Low pressure switch (2nd detection)

6. Refrigerant leakage (2nd detection)

10. The indoor unit stops due to an unknown error of the outdoor unit.

Communication error between remote controller and the Hydro unit / Hydro unit HT

Communication error between main and sub remote controller

Tracking error between remote controller and the Hydro unit / Hydro unit HT

Error due to exceeding maximum numbers of Hydro unit installation (16 units)

Error due to exceeding maximum numbers of hydro unit wired controller installation (2 units)

Error caused by installing mixed models

Remote controller's temperature sensor is disconnected or has problem

Data error on remote controller (Memory read/write error)

MSB or SVB R-32 sensor failure.

MSB/SVB refrigerant leak; all indoor units ceaseoperation.

MSB or SVB R-32 sensor failure.

MSB or SVB R-32 detecting sensor replacement warning after10years(3650days); product worksnormally.

MSB or SVB R-32 detecting sensor lifespan expired after10years3months(3740days); product doesnotwork.

Primary R-32 refrigerant leak detection; high-speed fan operates2minutes to determine leak again.

R-32 leak detection at affected indoor unit; product doesnotwork.

Indoor unit R-32 sensor failure.

Indoor unit R-32 detecting sensor replacement warning after10years(3650days); product worksnormally.

Indoor unit R-32 detecting sensor lifespan expired after10years3months(3740days); product doesnotwork.

Connected indoor unit stops because another affected indoor unit detects R-32.

Error on the sensor of water inlet pipe (Short or Open)

Error on the sensor of water outlet pipe (Short or Open)

Hot Water Tank Temperature sensor short/open

Error due to pipe rupture protection (Re-operation is impossible)

Error due to freeze prevention (Re-operation is possible)

Error due to freeze prevention (Re-operation is impossible)

Water temperature sensor on water outlet pipe is detached

Flow Switch Off Error, When Water pump is running

Six times detection for Flow Switch Error (Re-operation is possible, VHTC***S4-4P model only)

Error due to incorrect thermostat connection

Error on DC fan (Non-operating)

Water Tank Sensor configuration error

Error that the set temperature for disinfection operation is not reached, or, after reaching, the temperature fails to continue…

In recall mode control displays up to ten stored error codes. Sequential E 0 0 0 means none stored.

The outdoor control has lost communication with either the thermostat or indoor unit.

Error due to duplicated communication address

Possible issue with main power frequency (control requires 60 Hertz power).

Low 24 volts (18 or less volts) - Control will restart if the error recovers.

R-32 detection sensor 'Short' or 'Open' or 'Abnormal signal' error.

Indoor fan controller PCB overheat error

There is a delay in the outdoor unit responding to the system.

Error on room temperature sensor of indoor unit (Short or Open)

Error on EVA IN sensor of indoor unit (Short or Open)

Error on EVA OUT sensor of indoor unit (Short or Open)

The iComfort thermostat has lost communication with the outdoor unit for more than 3 minutes.

There is a hardware problem with the outdoor control.

An air-handler configuration jumper is missing.

The outdoor unit control parameters are corrupted.

Internal software error.

A leak of refrigerant has been detected by the refrigerant detection system.

The refrigerant detection system sensor is reporting a fault.

Error on float switch (2nd detection)

Communications with the refrigerant detection sensor has been lost or interrupted.

The refrigerant detection system sensor is of an incorrect type.

The refrigerant detection system controller has failed.

The outdoor unit ambient temperature sensor has malfunctioned. As a result the outdoor unit control will not perform low ambient…

Suction pressure transducer fault.

Suction Temperature Sensor has malfunctioned

Liquid Pressure Transducer Fault

Faulty outdoor liquid line sensor

Discharge temperaure too low

Discharge temperature/pressure too high

Error on thermal fuse of indoor unit (Open)

Indoor Blower communication failure - (includes indoor blower power outage)

Incorrect air handler model size and capacity selected or wrong motor. Check for proper configuring under Configuring Unit Size…

No air handler model size and capacity selected. Check for proper configuring under Configuring Unit Size Codes.

Main PBA - other PBA Communication error (All other PBA communication error)

Main PBA - other PBA communication error (Some of PBA communication) C002 : Fan PCB communication error C003 : INV1 communication…

Error on outdoor temperature sensor (Short or Open)

Error on outdoor COND OUT sensor (Short or Open)

Error on discharge temperature sensor of compressor 1 (Short or Open)

Indoor blower motor unable to start (seized bearing, stuck wheel, etc.).

Indoor blower motor over temperature (motor trip on internal protector)

Discharge air sensor (DATS) out of range, open or shorted. Code is only active in evenheat mode setting or on communicating…

Restricted airflow - Indoor blower motor is running at a reduced CFM (cutback mode **)

Indoor and outdoor unit capacity mismatch.

Error on OLP sensor (Short or Open)

Error on ESC IN temperature sensor (Short or Open)

Error on ESC OUT temperature sensor (Short or Open)

Global network connection error. This usually indicates there is a short or overladed resistance is to low) condition between…

Heat Pump or Air Conditioner Alert Code - The "O" relay on the outdoor board has failed.

Heat pump link not cut. AHC R-O link not cut for noncommunicating heat pump. Only on AHC Rev 2.4 or earlier.

Relay Y1 failure. AHC relay activated, but not respond back .

Relay Y2 failure. AHC relay activated, but not respond back .

Heat call with non-configured or mis-configured electric heat. Check for proper configuring under Configuring Electric Heat…

Heat section / Stage 1 failed (Pilot relay contacts did not close or the relay coil in electric heat did not energizing)

Heat section / Stage 2 failed.

Heat section / Stage 3 failed.

Heat section / Stage 4 failed.

Heat section / Stage 5 failed.

INVERTER PCB overheat error

Outdoor Fan#1 PCB overheat error

Compressor ran more than 18 hours in air conditioning mode.

Compressor system pressure trip.

Compressor short-cycling - running less than four minutes.

Compressor rotor locked.

Compressor open circuit.

Compressor open start circuit.

Compressor open run circuit.

Compressor contactor is welded.

Outdoor control secondary voltage is 18VAC or less.

The outdoor unit cycled off due to low suction pressure.

The low pressure fault has occurred 5 times within one hour. As a result, the outdoor unit is locked out.

The outdoor unit high pressure switch has opened.

The high pressure switch has opened 5 times within one hour. As a result, the outdoor unit is locked out.

The outdoor coil sensor has malfunctioned.

When in icomfort mode with non-communicating HP, defrost cycle running greater than 20 minutes in duration.

Compressor top cap switch exceeding thermal limit.

The inverter has detected a circuit problem.

The liquid line temperature sensor has malfunctioned.

Outdoor control has increased minimum compressor speed to allow for proper oil return due to low ambient temperature. NOTE -…

Excessive inverter alarms

The inverter has detected a DC peak fault condition.

The inverter has detected a high main input current condition.

On a call for compressor operation, if DC link power in inverter does not rise above 180 VDC for 2 and 3 ton models, 250 VDC for…

Compressor start failure

Error occurs when PFC detects an over-current condition of 100A, the control will display a moderate code. If condition is…

The inverter has detected a DC link high voltage condition.

The inverter has detected a compressor over-current condition

Outdoor control has lost communications with the inverter for greater than 3 minutes. Outdoor unit will stop all compressor…

Inverter internal error.

Inverter heat sink temperature exceeded limit. Occurs when the heat sink temperature exceeds the inverter limit. Inverter issues…

Heat sink temperature sensor fault has occurred (temperature less than 4 ºF or greater than 264ºF after 10 minutes of operation).

The inverter has detected a PFC over current condition. This would be caused by a high load condition, high pressure, or outdoor…

Compressor slowdown due to high input current.

Heat sink temperature is approaching limit. The compressor speed automatically slows to reduce heat sink temperature. The control…

Compressor slowdown due to high compressor current. Compressor current is approaching limit. The compressor speed automatically…

The top cap switch has opened 5 times within one hour. As a result, the outdoor unit is locked out.

Incorrect appliance unit size code selected.

Reversing valve position does not match the position commanded by the outdoor control. Verify reversing valve wiring connections…

Outdoor Fan#1 motor Operation error

Outdoor Fan#1 motor wire disconnection error

Outdoor Fan#1 IPM overheat error

Fan speed error

Error due to operation failure of inverter compressor

System stops due to full current control

Over current trip / PFC over current error

IPM Over Current(O.C)

Comp. Overload error

DC-Link voltage under/over error

Error due to abnormal rotation of the compressor or unconnected wire of compressor

Error on current sensor (Short or Open)

Error on DC-Link voltage sensor (Short or Open)

Outdoor unit EEPROM Read/Write error (Option)

Outdoor unit EEPROM Read/Write error (H/W)

Error on IPM Heat Sink sensor of inverter 1 (Short or Open)

Error on inverter fan 2

Outdoor Fan#1 motor overcurrent error

The EEV control board has stopped communicating with the outdoor control. Heat pump heating operation stopped. Check EEV…

Discharge pressure transducer fault. Discharge pressures sensor signal is out of range. The signal should be between 0.5 and 4.5…

Compressor Suction Temperature Sensor has malfunctioned. Check temperature sensor resistance in the applicable Installation and…

Overvoltage of H/W detect DC link

System EEV coil current too low. Heat pump operation can continue. Check system EEV coil connection to the EEV controller.

System EEV coil currrent too high. Heat pump heating operation stopped. Check system EEV coil connection to the EEV controller.

System superheat below 3 degrees F for more than 10 minutes. Heat pump heating operation stopped.

System superheat higher than 40 degrees F for more than 10 minutes. Heat pump heating operation stopped.

Inverter input voltage sensor error

FAN #1 motor current limiting error

Injection EEV coil current too high

FAN #1 motor output current error

FAN #1 motor voltage sensor error

FAN #1 IPM temperature sensor error

IPM overheat error on inverter 1

Error due to high pressure switch open or compressor down by high pressure

Smart install is not installed

Blockage detected on high pressure pipe during heating operation.

Gas leak detected

Error due to mismatching capacity of indoor and outdoor unit

DPM remote controller option error

Error due to mismatching indoor and outdoor unit

Inverter EEPROM Checksum error

Fan EEPROM CheckSum error

Compressor has been cycled OFF on utility load shedding.

Outdoor unit has been cycled OFF on low temperature protection.

External Contact Input ERROR

R-32 detection sensor life unpredictable error

R-32 detection sensor 2nd detecting error

R-32 detection sensor failure error

R-32 detection sensor replacement notification error

R-32 detection sensor Life-expiration error

Low flame current -- run mode.

Flame sensed out of sequence -- flame still present.

Low pressure switch failed open.

Low pressure switch failed closed.

High pressure switch failed open.

High pressure switch failed closed.

Low pressure switch opened during ignition trial or heating demand.

Limit switch open.

Watchguard -- Exceeded maximum number of retries.

Watchguard -- Exceeded maximum number of retries or last retry was due to pressure switch opening.

Watchguard -- Exceeded maximum number of retries or last retry was due to flame failure.

Watchguard -- Limit remained open longer than three minutes.

Watchguard -- Flame sensed out of sequence; flame signal gone.

Ignitor circuit fault -- Failed ignitor or triggering circuitry.

Low line voltage.

Hard lockout -- Rollout circuit open or previously opened.

Control failed self check, internal error (control will restart if error recovers).

No Earth ground (control will restart if error recovers).

Reversed line voltage polarity (control will restart if the error recovers).

Low secondary (24VAC) voltage.

No error in memory

Device communication problem - No other devices on BUS (Communication system).

Twin Communication Fault

Low line voltage.

Line voltage polarity reversed.

Ground not detected

High line voltage.

Line voltage frequency out-of-range.

Low 24V - Control will restart if the error recovers.

High 24V.

Poor ground detected (Warning only)

Unresponsive device. Communication only.

Active communicating thermostat signal missing for more than 3 minutes.

Control failed self-check, internal error, failed hardware. Will restart if error recovers. Integrated control not communicating.…

Control internal communication problem.

Corrupted control parameters (Verify configuration of system). Communicating only.

Refrigerant Leak detected

Refrigerant Leak Detector Sensor #1 fault

Refrigerant Leak Detector Sensor #2 fault

Refrigerant Leak Detector #1 Communication lost or invalid sensor dip switch configuration (DISABLE/ENABLE)

Refrigerant Leak Detector Sensor #2 Communication lost

Refrigerant Leak Detector Sensor #1 type incorrect

Refrigerant Leak Detector Sensor #2 type incorrect

Furnace Control Board Failure

Low GWP Test

Outdoor air temperature sensor failure. Only shown if shorted or out-ofrange.

Hard lockout - Rollout circuit open or previously open.

Indoor blower communication failure - Unable to communicate with blower motor.

Indoor blower motor mis-match - Indoor motor horsepower does not match unit capacity.

Appliance capacity / size is NOT programmed. Invalid unit codes refer to configuration flow chart.

Gas valve mis-wired.

Gas valve control relay contact shorted.

Gas valve second-stage relay failure.

Hot surface ignitor sensed open.

Low pressure switch failed open.

Low pressure switch failed closed.

High pressure switch failed open.

High pressure switch failed closed

Pressure switch open during trial for ignition or run mode.

Combustion air inducer calibration failure

Ignition on high fire

Low flame current - Run mode.

Flame sensed out of sequence - Flame still present.

Limit switch circuit open.

Discharge air temperature too high (gas heat only).

Soft lockout - Exceeded maximum number of retries. No flame current sensed.

Soft lockout - Exceeded maximum number of retries. Last retry failed due to the pressure switch opening.

Soft lockout - Exceeded maximum number of recycles. Last recycle due to the pressure switch opening.

Soft lockout - Exceeded maximum number of recycles. Last recycle due to flame failure.

Soft lockout - Exceeded maximum number of recycles. Last recycle failed due to the limit circuit opening or limit remained open…

Soft lockout - Flame sensed out of sequence. Flame signal is gone.

Soft lockout - Exceeded maximum number of calibration retries.

Ignitor circuit fault - Failed ignitor or triggering circuitry.

Heat air flow restricted below the minimum.

Indoor blower motor unable to start due to obstructed wheel, seized bearings.

Combustion air inducer motor amp draw is too high.

Indoor blower motor temperature is too high.

Discharge error temperature sensor failure. Only shown if shorted or out of range.

Heat rate reduced to match indoor blower air flow.

Restricted air flow in cooling or continuous fan mode is lower than cfm setting.

Indoor or outdoor unit capacity mismatch.

Global network connection - Communication link problem.

Relay “Y1” stuck on interated control.

No 24 Volt output on Y1 to C with non-communicating outdoor unit.

No 24 Volt output on Y2 to C with noncommunicating outdoor unit.

No 24 Volts between R & O with non-communicating outdoor unit (Dual fuel module required for heat pump application).

Interlock switch sensed open for 2 minutes.

Low GWP Relay Stuck

LSOM - Compressor internal overload tripped.

LSOM - Compressor ran more than 18 hours in air conditioning mode.

LSOM - Outdoor unit system pressure trip.

LSOM - Compressor short-cycling (Running less than 4 minutes).

LSOM - Compressor rotor locked.

LSOM - Compressor open circuit.

LSOM - Compressor open start circuit.

LSOM - Compressor open run circuit.

LSOM - Compressor contactor is welded.

LSOM - Compressor low voltage.

No communication for 2 minutes between indoor units (Communication error for more than 2 minutes)

The indoor unit receiving the communication error from the outdoor unit

Error indicating a shor/open or fault signal in the refrigerant leak sensor

Error on indoor temperature sensor (Short or Open)

Error on Eva-in sensor (Short or Open)

Error on Eva-out sensor (Short or Open)

Discharge sensor error (Short or Open)

Detection of the float switch

Error of Fan motor in the indoor unit

Error of EEPROM

Error of Option setting

When sending the communication error from the outdoor unit, the mismatching of the communication numbers and installed numbers…

Outdoor unit tracking 3 minutes error

Emergency alarm system on (Emergency Stop)

Error indicating the refrigerant leak sensor's lifespan cannot be predicted

Error indicating a primary refrigerant leak detected

Error indicating a secondary refrigerant leak detected

Error indicating a malfunction of the refrigerant leak sensor

R-32 detection sensor replacement alarm

R-32 detection sensor unavailable alarm

Error indicating another indoor unit that shares the outdoor unit detects the R-32 refrigerant.