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Heat pumps · Error codes

Climaveneta / De Longhi Professional heat pump error codes

Climaveneta / De Longhi Professional · No longer sold new in the UK. 96 codes across 3 product families, each taken from the manufacturer’s manuals.

Find a Climaveneta / De Longhi Professional engineer →96 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.

96 codes

CodeMeaningStops?Homeowner check?
A001
BT1 system heat exchanger water inlet temperature probe
Not statedYes
A002
BT2 system heat exchanger water outlet temperature probe
Not statedYes
A003
BT8 DHW storage temperature probe
Not statedYes
A005
BT9 storage tank temperature probe
Not statedYes
A006
BT11 outside air temperature probe
Not statedYes
A013
F1 high pressure switch
YesYes
A019
Difference between low and high pressure in refrigerant circuit too low
YesYes
A022
Operation outside of limits
Not statedYes
A025
Differential pressure switch / system flow switch F3 activated
Not statedYes
A030
Compressor operating hours reached
Not statedYes
A033
System pump operating hours reached
Not statedYes
A034
Domestic hot water pump operating hours reached
Not statedYes
A035
Mixed zone pump operating hours reached
Not statedYes
A036
Fan operating hours reached
Not statedYes
A038
System heat exchanger frost prevention alarm
Not statedYes
A041
DHW storage temperature too high
Not statedYes
A042
Inside frost prevention alarm
Not statedYes
A054
Legionella prevention alarm
Not statedYes
A055
Temperature probe N-THC n.1
Not statedYes
A056
Address setting error on remote terminal supplied with the unit
Not statedYes
A057
Address setting error on expansion module 2
Not statedYes
A058
Temperature probe in low temperature zone LT2, expansion 2
Not statedYes
A063
Address setting error on expansion module 3
Not statedYes
A064
Temperature probe in low temperature zone LT3, expansion 3
Not statedYes
A075
Water temperature too high in mixed circuit, expansion module 1
Not statedYes
A077
Water temperature too high in mixed circuit, expansion module 2
Not statedYes
A094
End defrost due to maximum time
Not statedYes
A095
Temperature probe N-THC n.2
Not statedYes
A096
Address setting error on zone remote terminal
Not statedYes
A097
Temperature probe N-THC n.3
Not statedYes
A098
Address setting error on zone remote terminal
Not statedYes
A099
Temperature probe N-THC n.4
Not statedYes
A100
Address setting error on zone remote terminal
Not statedYes
A101
Temperature probe N-THC n.5
Not statedYes
A102
Address setting error on zone remote terminal
Not statedYes
A103
Address setting error on expansion module 1
Not statedYes
A104
Low temperature zone LT1 temperature probe, expansion 1
Not statedYes
A109
Low pressure alarm from low pressure switch
YesYes
A114
Solar/pool module address setting error
Not statedYes
A115
Solar/pool module general alarm
Not statedYes
A116
Master unit not connected, cascade control
Not statedYes
A117
Slave unit not connected, cascade control
Not statedYes
A120
Water temperature too high in mixed circuit, expansion module 3
Not statedYes
A121
Temperature probe N-THC n.6
Not statedYes
A122
Address setting error on zone LT3 remote terminal
Not statedYes
A123
i-KI/i-KIR general alarm - problems relating to the heat pump (see heat pump PCB display codes)
YesYes
A124
Humidity probe N-THC n.1
Not statedYes
A125
Humidity probe N-THC n.2
Not statedYes
A126
Humidity probe N-THC n.3
Not statedYes
A127
Humidity probe N-THC n.4
Not statedYes
A128
Humidity probe N-THC n.5
Not statedYes
A129
Humidity probe N-THC n.6
Not statedYes
Er01
High pressure switch tripped; manual reset after 3 activations in one hour; incorrect phase connection (three-phase models)
YesYes
Er03
High pressure alarm from pressure transducer
YesYes
Er05
Low pressure switch tripped; manual reset after 4 activations in one hour
YesYes
Er07
Low pressure alarm from pressure transducer
YesYes
Er20
Differential pressure switch or flow switch tripped; manual reset if active >30 s
YesYes
Er25
Differential pressure switch or well/source water flow switch activated; manual reset if active >30 s
YesYes
Er30
Frost prevention alarm (manual reset)
YesYes
Er31
Well / source frost prevention alarm (manual reset) - check BT3 position, source flow
YesYes
Er35
High water outlet temperature (automatic reset)
YesYes
Er45
Clock fault error (automatic reset) - replace controller
NoYes
Er46
Clock to be set error (automatic reset) - set date and time
NoYes
Er47
HSW11 communication error with remote keypad (only if remote keypad fitted)
Varies by modelYes
Er48
Anti-Legionella cycle not completed
Varies by modelYes
Er60
Faulty BT1 water return sensor (automatic reset)
YesYes
Er61
Faulty BT2 water outlet sensor (automatic reset)
YesYes
Er64
Faulty BT3 source water outlet sensor (automatic reset)
YesYes
Er66
Faulty domestic hot water sensor BT4
Varies by modelYes
Er68
Outside air sensor BT3 malfunction (automatic reset)
YesYes
Er75
Pressure transducer malfunction
YesYes
Er81
Compressor maintenance interval reached
NoYes
Er85
Water pump maintenance interval reached
NoYes
Er90
Maximum alarm log size exceeded
NoYes
PCB-A0
DC voltage error
YesYes
PCB-A1
Outlet (discharge) temperature error
YesYes
PCB-A2
Overcurrent protection - direct current (DC) measurement
YesYes
PCB-A3
Current transformer disconnected
YesYes
PCB-A4
Overcurrent protection - alternating current (AC) measurement
YesYes
PCB-A5
Abnormal compressor rotation
YesYes
PCB-A6
Return (suction) temperature probe error
YesYes
PCB-A7
Defrost temperature probe error
YesYes
PCB-A8
Outlet (discharge) temperature probe error
YesYes
PCB-C0
Power supply module error
YesYes
PCB-C1
Upper fan motor error
YesYes
PCB-C2
Outside temperature probe error
YesYes
PCB-C3
Lower fan motor error / fan motor error (single-fan sizes)
YesYes
PCB-C4
Power module temperature increase (above 110 C)
YesYes
PCB-C5
Power supply module temperature probe error
YesYes
PCB-C6
Control board (PCB-controller) error
YesYes
PCB-C7
PCB serial interface error
YesYes
PCB-C8
PCB serial converter error
YesYes
PCB-CC
Heat pump PCB controller serial error
YesYes
PCB-E4
Water outlet temperature probe error
YesYes
PCB-E5
Water return temperature probe error
YesYes
PCB-FU
High pressure switch activated
YesYes