Heat pump service with refrigeration gauges

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.

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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

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