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Heat pumps · Error codes

Kronoterm heat pump error codes

Kronoterm · A niche brand in the UK. 87 codes across 2 product families, each taken from the manufacturer’s manuals. Kronoterm technical support ↗

Find a Kronoterm engineer →87 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.

87 codes

CodeMeaningStops?Homeowner check?
2114-b3
High pressure
YesYes
2114-b7
Low pressure
YesYes
2114-b8
CP phase control
YesYes
2114-b9
No water flow
YesYes
2114-b14
Efficiency
YesYes
2115-b0
Failure module 1
YesYes
2115-b1
Failure module 2
YesYes
2115-b4
Too high compressor temperature
YesYes
2115-b5
Communication failure - outdoor unit
YesYes
2115-b8
Max. number of defrosting
YesYes
2116-b2
Temperature sensor fault - condenser inlet (T28)
YesYes
2116-b3
Temperature sensor fault - condenser outlet (T27)
YesYes
2117-b10
Outlet minimum temperature
YesYes
2117-b13
Remote shutdown
NoYes
2119-b14
No model set
YesYes
2119-b15
Outdoor unit fault
YesYes
2124-b7
No response from cascade modules
NoYes
2124-b8
Cascade module 1 has to be inspected
NoYes
2124-b9
Cascade module 2 has to be inspected
NoYes
2124-b10
Cascade module 3 has to be inspected
NoYes
2124-b11
Cascade module 4 has to be inspected
NoYes
2126-b0
Communication failure with cascade module 1
YesYes
2126-b1
Communication failure with cascade module 2
YesYes
2126-b2
Communication failure with cascade module 3
YesYes
2126-b3
Communication failure with cascade module 4
YesYes
2126-b8
Failure on cascade module 1
YesYes
2126-b9
Failure on cascade module 2
YesYes
2126-b10
Failure on cascade module 3
YesYes
2126-b11
Failure on cascade module 4
YesYes
2186-b0
Heating loop thermostat failure 1
YesYes
2186-b1
Heating loop thermostat failure 2
YesYes
2186-b2
Heating loop thermostat failure 3
YesYes
2186-b3
Heating loop thermostat failure 4
YesYes
2330-b5
Refrigerant loss
NoYes
2335-b3
AC over voltage fault
YesYes
2335-b4
AC under voltage fault
YesYes
2335-b8
Input loss of phase fault
YesYes
2339-b0
Temperature sensor fault - DHW (T1)
YesYes
2339-b1
Temperature sensor fault - outdoor heating system (T2)
YesYes
2339-b2
Temperature sensor fault - 1st loop (T3)
YesYes
2339-b3
Temperature sensor fault - 2nd loop (T4)
YesYes
2339-b4
Temperature sensor fault - 3rd loop (T5)
YesYes
2339-b5
Temperature sensor fault - 4th loop (T6)
YesYes
2339-b6
Temperature sensor fault - pool (T7)
YesYes
2339-b7
Temperature sensor fault - solar/biomass (T8)
YesYes
2339-b8
Temperature sensor fault - buffer tank 1 (T9)
YesYes
2339-b9
Temperature sensor fault - buffer tank 2 (T10)
YesYes
2339-b12
Temperature sensor fault - outlet HP (T15)
YesYes
2339-b13
Temperature sensor fault - inlet HP (T16)
YesYes
2339-b14
Temperature sensor fault - outlet after elect. heater (T13)
YesYes
2339-b15
Temperature sensor fault - inlet indoor unit (T14)
YesYes
2340-b7
Pressure sensor fault - heating system (T25)
YesYes
2340-b8
Flow sensor fault - heating system (T26)
YesYes
2340-b9
SD card fault
YesYes
2341-b4
Low pressure - heating system
NoYes
ALARM-DHW
Device unable to heat DHW above the minimum set value 3 times
YesYes
ALARM-RTC-FAIL
Error on the PLC frequency oscillator
YesYes
Carel-EEV-error
The Carel (EEV) controller is malfunctioning
YesYes
Carel-probe-error
Carel probe 1-4 not connected or damaged
YesYes
Caution-flow
Flow switch not closed - no or insufficient water flow; after 120 s device enters compressor protection (Standby) and retries
PartlyYes
Comp-temp-too-high
Too high compressor temperature
YesYes
Defrost-T-Flow-ALARM
Return water temperature during defrost too low - HP lacks energy to defrost
YesYes
Efficiency
The device does not heat / does not generate enough heat
YesYes
ERROR-Cascade
Individual device did not respond 3x during cascade verification (MD1 to MD4)
PartlyYes
ERROR-HeatSourceTemp
Source temperature outside operating range
YesYes
ERROR-NO-WATER
Heat source pump switched off or shortage of water for the heat source / insufficient flow of medium between HP and heating system
YesYes
ERROR-Sensor
Alarm: one of the sensors (1-18) is not connected or is damaged
YesYes
ERROR-Thermostat
Room corrector (KT-1/KT-2) 1-4 not connected properly or malfunctioning
PartlyYes
HpCool
Alarm: refrigerant pressure too high during cooling
YesYes
HpDHW
Alarm: refrigerant pressure too high during DHW heating
YesYes
HpHeat
Alarm: refrigerant pressure too high during heating
YesYes
INV-Error-xx
External device (inverter) error number xx
YesYes
Low-Comp-temp
Compressor temperature too low; after three indications the PZ PROG is activated
YesYes
Low-Cond-temp
Plate heat exchanger temperature too low; after three indications PZ PROG activated
YesYes
LpCool
Alarm: refrigerant pressure too low during cooling (displayed "LpCol")
YesYes
LpDHW
Alarm: refrigerant pressure too low during DHW heating
YesYes
LpHeat
Alarm: refrigerant pressure too low during heating (displayed "LpHea")
YesYes
Max-dT
Temperature difference between supply and return too high
YesYes
Max-ODT-h
Maximum number of defrosts per hour reached
YesYes
MODULE-5-6-ALARM
No communication with Carel EEV 1 (module 5) / EEV 2 (module 6)
YesYes
MODULE-ALARM
Malfunction of one of the modules (MODULE 1-4 ALARM); device restarts automatically after the error is resolved
YesYes
MODULE-INV-ALARM
No connection with the external device (inverter)
YesYes
OC1-communication
No communication with main circulation pump (CP)
Not statedYes
OC2-communication
No communication with source circulation pump (CP)
Not statedYes
RESET-MODUL
One of the modules is in self-reset process
Not statedYes
S01
Initialization error - incorrect initialization of indoor and outdoor unit, incorrect KT-2A operation mode setting or incorrectly connected communication cable
YesYes
Tz
Alarm: overvoltage, undervoltage or inverted phase sequence in the electrical supply
YesYes