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Heat pumps · Error codes

Warmflow heat pump error codes

Warmflow · A niche brand in the UK. 98 codes across 4 product families, each taken from the manufacturer’s manuals. Warmflow technical support ↗

Find a Warmflow engineer →98 codes · reviewed 23 September 2026

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Type the code on your display or a word from its meaning. Each code opens its own page with what it means, whether it is safe and what you can check.

98 codes

CodeMeaningStops?Homeowner check?
B01
Probe B01 fault or disconnected - Brine Out temp sensor
Not statedYes
B02
Probe B02 fault or disconnected - Brine In temp sensor
Not statedYes
B03
Probe B03 fault or disconnected - DHW temp sensor
Not statedYes
B04
Probe B04 fault or disconnected - Heating return
Not statedYes
B05
Probe B05 fault or disconnected - Heating flow
Not statedYes
B06
Probe B06 fault or disconnected - Brine flow meter
Not statedYes
B07
Probe B07 fault or disconnected - Heating flow meter
Not statedYes
B08
Probe B08 fault or disconnected - External temperature
Not statedYes
Brine-circuit-freeze-risk
Brine circuit freeze risk
Not statedYes
Brine-flow-rate-too-low
Brine flow rate too low or blocked
Not statedYes
Commission-mode-enabled
Commission mode enabled
PartlyYes
E003
Driver Board Self Test
YesYes
E04
Electric Overheat Protection
YesYes
E06
Excess Temp. Diff. Between Inlet & outlet
YesYes
E08
Communication Error
YesYes
E11
High Pressure Protection
YesYes
E12
Low Pressure Protection
YesYes
E19
Primary Anti-freezing Protection
YesYes
E29
Secondary Anti-freezing Protection
YesYes
E030
Insufficient Defrosting Water Flow Alarm
YesYes
E032
Low Flow Error
YesYes
E051
Compressor Overload
YesYes
E065
Outlet Water Temp. Overtemp.
YesYes
E071
Outlet Water Temp. Lowtemp.
YesYes
E081
DC Fan Motor 1 & PCB Communication Error
YesYes
E082
DC Fan Motor 2 & PCB Communication Error
YesYes
E084
Display and Main Controller Not Compatible
YesYes
E101
Compressor Overcurrent
YesYes
E103
Fan Motor 1 Overload
YesYes
E171
Anti-freezing Protection
YesYes
E203
Fan Motor 2 Overload
YesYes
F00
Inverter IPM Overcurrent Shutdown
YesYes
F01
Compressor Start-up Failure
YesYes
F03
Power Factor Correction (PFC) Error
YesYes
F05
DC Bus Overload
YesYes
F06
DC Bus Underload
YesYes
F07
AC Input Underload
YesYes
F08
AC Input Overload
YesYes
F09
Input Voltage Read Error
YesYes
F10
AC Power Overvoltage Error
YesYes
F11
DSP Communication Error
YesYes
F12
DSP and PFC Communication Error
YesYes
F13
IPM Over Temperature Protection
YesYes
F14
Compressor Lacking Phase
YesYes
F15
Input Voltage Lacking Phase
YesYes
F16
Weak Magnetism Error
YesYes
F17
Module/Radiator Sensor Error
YesYes
F18
IPM Current Read Error
YesYes
F20
IGBT Power Device Error
YesYes
F21
Overspeed Error
YesYes
F22
AC Input Over Current Error
YesYes
F23
EEPROM Alarm
YesYes
F24
EEPROM Alarm
YesYes
F25
LP 15V Error
YesYes
F26
IGBT Power Device Over Temperature
YesYes
F29
EEPROM Alarm
YesYes
F031
DC Fan Motor 1 Error
YesYes
F032
DC Fan Motor 2 Error (AS03 models only)
YesYes
F33
Compressor Current Frequency Reduction Error
YesYes
F101
Fan Driver Power input Phase Error
YesYes
F102
Fan Start Error
YesYes
F105
Fan external Overcurrent Error
YesYes
F106
Fan IPM Overheat Error
YesYes
F109
Fan Driver Overspeed Error
YesYes
F112
Fan Current sampling Error
YesYes
F113
Fan internal Overcurrent Error
YesYes
F120
Fan Driver Temperature Sensor Error
YesYes
F151
Comp. Driver and PCB Communication Fault
YesYes
Hardware-Alarm
Hardware Alarm
Not statedYes
Heating-circuit-freeze-risk
Heating circuit freeze risk
Not statedYes
Heating-flow-rate-too-low
Heating flow rate too low or blocked
Not statedYes
NO-LINK
NO LINK (user interface not communicating)
Not statedYes
P01
Heating Return Temperature Sensor Error
YesYes
P02
Heating Flow Temperature Sensor Error
YesYes
P02a
Mix Tube Outlet Water Temp. Sensor Fault
YesYes
P03
DHW Cylinder Temperature Sensor Error
YesYes
P03a
Buffer Tank Temp. Sensor
YesYes
P04
Ambient Temperature Sensor Error
YesYes
P013
Heating Return Temperature Sensor Error
YesYes
P17
Suction Temperature Sensor Error
YesYes
P018
DHW Return Temperature Sensor Error
YesYes
P023
Heating Flow Temperature Sensor Error
YesYes
P028
DHW Flow Temperature Sensor Error
YesYes
P42
Room Temperature Sensor Error
YesYes
P101
EVI Inlet Temperature Sensor Error
YesYes
P102
EVI Outlet Temperature Sensor Error
YesYes
P152
Distributor Tube Temp. Sensor Fault
YesYes
P153
Evaporator Temperature Sensor Error
YesYes
P181
Discharge Temperature Sensor Error
YesYes
P182
Discharge Overheat Temperature Sensor Error
YesYes
P191
Anti-freezing Temp. Sensor Fault
YesYes
PP1
Discharge Pressure Sensor Error
YesYes
PP2
Suction Pressure Sensor Error
YesYes
PP11
Pressure Sensor Error
YesYes
Service-due
Service is due
NoYes
Software-Alarm
Software Alarm
Not statedYes
TC
No Cooling at Low AT Protection
YesYes
TP
Low Ambient Temperature Warning
YesYes