Mitsubishi Ecodan & Daikin Altherma Fault Codes / Error Codes
Below are some common fault codes for Mitsubishi Ecodan and Daikin Altherma air to water heat pumps. If you need help interpreting the error code or fixing your problem then call us on 01242 821438. We currently cover Gloucestershire, Oxfordshire, Hererfordshire, Worcestershire and Wiltshire.
IMPORTANT: These codes have been supplied for your information, however we recommend that all servicing of heat pump units should be carried out by a suitably qualified F-Gas engineer. Failure to comply may result in serious harm or fatality.
Can't find what you're looking for? Try one of the following sections:
Heat pump service and maintenance
Heat pump frequently asked questions
Heat pump user guides and manuals
Our engineers service and repair heat pumps on a daily basis. Call us on 01242 821438 for expert help and advice.
Mitsubishi Ecodan heat pump error codes / fault codes
Applicable model numbers: PUHZ-W50VHA, PUHZ-W85VHA2, PUHZ-W112VHA2, PUHZ-HW140VHA2, PUHZ-HW140YHA2, PUHZ-SW40VHA, PUHZ-SW75VHA, PUHZ-SW120VHA
| Error Code | Description |
|---|---|
| F3 | Low pressure switch failure |
| F5 | High pressure switch failure |
| F9 | Both pressure switch contacts are open at the same time |
| EA | Mis-wiring fault between FTC and Ecodan |
| EB | Mis-wiring fault between FTC and Ecodan |
| EC | Unit cannot finish start up process |
| U1 | Ecodan high pressure fault |
| U2 | Ecodan high compressor discharge temperature |
| U3 | Ecodan discharge thermistor problem |
| U4 | Open or close circuit Ecodan thermistors |
| U5 | Inverter heat sink overheat protection |
| U6 | Inverter/Compressor over current |
| U8 | Ecodan fan motor problem |
| U9 | Over voltage or under voltage |
| UD | Overheat protection |
| UF | Compressor over current/Compressor lock |
| UH | Abnormal running current |
| UL | Open circuit |
| UP | Over current |
| E0 | Transmitting Error |
| E1 | Faulty controller |
| E3 | Transmitting Error |
| E4 | Receiving Error |
| E5 | Receiving Error |
| E6 | Indoor/Outdoor communication error |
| E8 | Indoor/Outdoor communication error |
| E9 | Indoor/Outdoor communication error |
| EF | Non-defined error code - noise interference |
| ED | Serial communication fault between Ecodan main board and Ecodan inverter board |
| P1 | Flow temp sensor fault |
| P6 | Over heating at heat exchanger |
| P8 | No temp change at plate heat exchanger |
| P9 | TH5 Fault |
| PE | Inlet water temp fault |
Daikin Altherma heat pump error codes / fault codes
Applicable model numbers: ERLQ004CAV3, ERLQ006CAV3, ERLQ008CAV3, ERLQ011CAV3, ERLQ014CAV3, ERLQ016CAV3, ERLQ004CBV3, ERLQ006CBV3, ERLQ008CBV3, ERLQ011CBV3, ERLQ014CBV3, ERLQ016CBV3, ERHQ004BAV3, ERHQ006BAV3, ERHQ008BAV3, ERHQ011BAV3, ERHQ014BAV3, ERHQ016BAV3, EBHQ004BAV3, EBHQ006BAV3, EBHQ008BAV3, EBHQ011BAV3, EBHQ014BAV3, EBHQ016BAV3, ERHQ004BBV3, ERHQ006BBV3, ERHQ008BBV3, ERHQ011BBV3, ERHQ014BBV3, ERHQ016BBV3, ERHQ004BCV3, ERHQ006BCV3, ERHQ008BCV3, ERHQ011BCV3, ERHQ014BCV3, ERHQ016BCV3, ERHQ004AAV3, ERHQ006AAV3, ERHQ008AAV3, ERHQ011AAV3, ERHQ014AAV3, ERHQ016AAV3, ERHQ004ABV3, ERHQ006ABV3, ERHQ008ABV3, ERHQ011ABV3, ERHQ014ABV3, ERHQ016ABV3, ERHQ004ACV3, ERHQ006ACV3, ERHQ008ACV3, ERHQ011ACV3, ERHQ014ACV3, ERHQ016ACV3, RLQ011CW1, ERLQ014CW1, ERLQ016CW1, ERSQ011AV1, ERSQ014AV1, ERSQ016AV1, RSQ011AY1, ERSQ014AY1, ERSQ016AY1
| Error Code | Description |
|---|---|
| A1 | Indoor unit HT & LT: Printed circuit board defect |
| A5 | Indoor unit LT: Liquid sensor error |
| A6 | Indoor unit HT: Water pump error |
| A9 | Indoor unit HT: Expansion valve drive error R410A circuit |
| AA | Indoor unit LT: Thermal protector in back up heater open |
| AC | Indoor unit LT: Thermal protector in cylinder open, cylinder over heat |
| AJ | Indoor unit HT: Capacity plug missing |
| C0 | Indoor unit LT: Water pump stopped but flow switch still made |
| C1 | Indoor Unit HT: Failure of transmission between the indoor printed circuit board and control board |
| C4 | Indoor unit HT & LT: Malfunction of liquid thermistor (R410A) |
| C5 | Cylinder HT: Malfunction of tank thermistor |
| C9 | Indoor unit HT: Return water temperature thermistor fault |
| CA | Indoor unit HT: Leaving water temperature thermistor error |
| CJ | Indoor unit HT: Malfunction of thermostat sensor in the remote controller |
| E1 | Outdoor unit HT & LT: Printed circuit board defect |
| E1-3 | Indoor unit HT: Pcb defect |
| E3-1 | Outdoor unit HT & LT: High Pressure |
| E3-12 | Indoor unit HT (R134A): High pressure |
| E4 | Outdoor unit HT & LT: Low Pressure (R410A) |
| E4-6 | Indoor unit HT: Low pressure (R134A) |
| E5 | Outdoor unit HT & LT: Compressor lock or service valves shut (R410A) |
| E5-6 | Indoor unit HT: Compressor lock (R134A) |
| E6 | Outdoor unit LT: Compressor malfunction, over current, failed to start |
| E7 | Outdoor unit HT & LT: Fan motor malfunction or locked |
| E8 | Outdoor unit LT: Compressor malfunction, over current, failed to start |
| E9 | Outdoor unit HT & LT: Expansion valve drive error (R410A) |
| E9-17 | Indoor unit HT: Expansion valve drive error K2E (R134A) |
| EA | Outdoor unit LT: 4 way valve failed to change over or indoor liquid line thermistor fault |
| EC | Cylinder LT: Domestic hot water cylinder thermistor fault |
| F3 | Outdoor unit HT & LT: Abnormal discharge pipe temperature or faulty thermistor (R410A) |
| F3-19 | Indoor unit HT: Abnormal discharge pipe temperature (R134A) |
| F6 | Outdoor unit LT: Condensing temperature too high or faulty thermistor (R410A) |
| H0 | Outdoor unit LT: Current sensor faulty, compressor disconnected or faulty outdoor printed circuit board (R410A) |
| H3 | Outdoor unit LT: High pressure switch activation, possible faulty HP switch or faulty printed circuit board (R410A) |
| H6 | Outdoor unit LT: Compressor start up failure (R410A) |
| H8 | Outdoor unit LT: Current transformer failure, outdoor printed circuit board fault (R410A) |
| H9 | Outdoor unit HT & LT: Malfunction of outside air thermistor R1T (R410A) |
| HC | Cylinder LT: Domestic hot water cylinder thermistor fault |
| J1 | Outdoor unit LT: Pressure sensor malfunction, pressure transducer (R410A) |
| J3 | Outdoor unit HT & LT: Malfunction of the discharge pipe thermistor (R410A) |
| J3-46 | Indoor unit HT: Malfunction of the discharge pipe thermistor R6T (R134A) |
| J5 | Outdoor unit HT & LT: Suction pipe thermistor error R3T R5T (R410A) |
| J5 | Indoor unit HT: Suction pipe thermister error R7T (R134A) |
| J6 | Outdoor unit HT & LT: Malfunction of thermistor for outdoor heat exchanger (R410A) |
| J7 | Outdoor unit HT & LT: Malfunction of liquid pipe thermistor on outdoor coil (R410A) |
| J8 | Outdoor unit LT: Malfunction of liquid pipe thermistor on outdoor coil (R410A) |
| J9 | Outdoor Unit HT: Malfunction of thermistor for subcooling heat exchanger gas pipe R4T (R410A) |
| JA | Outdoor unit HT: Malfunction of high pressure sensor X17A (transducer) (R410A) |
| JA-16 | Indoor unit HT: Malfunction of high pressure sensor X17A (transducer) (R134A) |
| JC | Outdoor unit HT: Malfunction of low pressure sensor X18A (transducer) (R410A) |
| JC-16 | Indoor unit HT: Malfunction of low pressure sensor X18A (transducer) (R134A) |
| L1 | Outdoor unit HT & LT: Malfunction of printed circuit board A1P (R410A) |
| L1-30 | Indoor unit HT: Malfunction of printed circuit board A4P (R134A) |
| L3 | Outdoor unit LT: Electrical switch box temperature rise >85oC (R410A) |
| L4 | Outdoor Unit HT & LT: Malfunction of inverter radiating fin temperature rise >83oC (R410A) |
| L4-8 | Indoor Unit HT: Malfunction of inverter radiating fin temperature rise >83oC R8T (R134A) |
| L5 | Outdoor Unit HT & LT: Malfunction of inverter compressor lock, over current (R410A) |
| L5-13 | Indoor Unit HT: Malfunction of inverter compressor lock, over current (R134A) |
| L8 | Outdoor Unit HT & LT: Malfunction of inverter compressor overload, current abnormal (R410A) |
| L8-10 | Indoor Unit HT: Malfunction of inverter compressor overload, current abnormal (R134A) |
| L9 | Outdoor Unit HT & LT: Malfunction of inverter start up, defect compressor or differential, stall prevention (R410A) |
| L8-9 | Indoor Unit HT: Malfunction of inverter start up, defect compressor or differential, stall prevention (R134A) |
| LC | Outdoor Unit HT & LT: Malfunction of transmission between inverter and control board A1P or A2P (R410A) |
| LC-29 | Indoor Unit HT: Malfunction of transmission between inverter and control board A4P or A5P (R134A) |
| LH-2 | Indoor Unit HT: Malfunction of inverter pcb (R134A) |
| P1 | Outdoor unit HT & LT: High Voltage of capacitor in main inverter circuit (R410A) |
| P1-6 | Indoor unit HT: High Voltage of capacitor in main inverter circuit (R134A) |
| P4 | Outdoor unit LT: Electrical switch box fin thermistor fault (R410A) |
| PJ | Indoor unit LT: Capacity adapter not installed (R410A) |
| PJ-11 | Indoor unit HT: Incorrect combination of indoor printed circuit board or capacity adapter not installed (R134A) |
| U0 | Outdoor unit HT & LT: Low pressure drop due to refrigerant shortage or electronic expansion valve failure (R410A) |
| U2 | Outdoor unit HT & LT: Power supply insufficient or Instantaneous failure, low or high voltage detected (R410A) |
| U2-20 | Indoor unit HT: Power supply insufficient or Instantaneous failure, low or high voltage detected |
| U2-20 | Indoor unit HT: High low voltage problem |
| U2-21 | Indoor unit HT Converter problem (R134A) |
| U4 | Outdoor Unit HT & LT: Malfunction of transmission between indoor and outdoor unit (R410A) |
| U4-4 | Indoor Unit HT: Malfunction of transmission between the indoor and outdoor unit |
| U4-4 | Indoor Unit HT: DIII Communication error (R134A) |
| U5 | Indoor Unit HT & LT: Malfunction of transmission between the remote control and indoor unit |
| U5-0 | Indoor Unit HT: Malfunction of transmission between the remote controllers main and sub controller (R134A) |
| U7 | Outdoor Unit LT: Signal transmission failure on outdoor printed circuit board faulty (R410A) |
| U8 | Indoor Unit HT: Malfunction of transmission between the main and sub controller (R134A) |
| UA | Indoor Unit HT: Excessive number of indoor units or mis matched board replaced and capacity not set (R134A) |
| UA-13 | Outdoor Unit HT: Excessive number of indoor units or mis matched board replaced and capacity not set (R410A) |
| UA | Indoor & Outdoor Unit LT: Interconnecting wiring crossed (R410A) |
| UF | Indoor Unit HT: Unit has not been initialised up to 10 minutes |
| UF-6 | Indoor Unit HT: QA wiring problem |
| UF-10 | Indoor Unit HT: Transmission problem with outdoor unit (R134A) (R410A) |
| UF | Outdoor Unit LT: Transmission problem between indoor & outdoor unit or gas shortage (R410A) |
| UH-0 | Indoor Unit HT: Defect of transmission wiring,indoor printed circuit board failure or outdoor printed circuit board failure (R134A) (R410A) |
| 7H | Indoor unit LT: Flow switch activated, water flow rate too low or blocked inlet strainer |
| 80 | Indoor unit LT: Inlet water temperature thermistor error |
| 81 | Indoor unit LT: Outlet water temperature thermistor error |
| 89 | Indoor unit LT: Outlet water temperature thermistor error, freeze up or water temperature too low |
| 8H | Indoor unit LT: Outlet water temperature too high, back up heater welded shut or thermistor out of calibration |
Why not call or visit our showroom to discuss your requirements
Call 01242 821438 to book an appointment
We are open Monday to Friday from 9:00am to 5:00pm