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Heat pumps · Error codes

Stiebel Eltron heat pump error codes

Stiebel Eltron · An established brand in the UK. 634 codes across 5 product families, each taken from the manufacturer’s manuals. Stiebel Eltron technical support ↗

Find a Stiebel Eltron engineer →634 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.

634 codes

CodeMeaningStops?Homeowner check?
01
Anode
PartlyYes
02
The high limit safety cut-out has tripped: The electric emergency/booster heater has overheated and was stopped by the high limit safety cut-out.
YesYes
03
High pressure switch: The high pressure switch has responded five times within a compressor runtime of two hours. The heat pump will shut down.
YesYes
04
Low pressure switch: The low pressure switch has responded five times in five hours. The heat pump will shut down.
YesYes
05
Extract air fan: The fan is blocked.
YesYes
06
Supply air fan: The fan is blocked.
YesYes
07
Exhaust air fan: The fan is blocked. The heat pump will be locked out.
YesYes
08
Hot gas max.: The compressor was shut down for safety reasons.
YesYes
09
EVE min.: The heat pump will shut down.
YesYes
10
Flow max: Heat generators are disabled until the flow temperature has fallen; enabled heat generator cycles on and off.
PartlyYes
11
Low pressure sensor: The low pressure sensor does not deliver a plausible signal (< 2 mA for longer than 10 s). The heat pump is blocked in cooling mode.
PartlyYes
12
High pressure sensor: The high pressure sensor does not deliver a plausible signal (< 2 mA for longer than 10 s).
PartlyYes
13
EVE refrigerant shortage: The 'Refrigerant shortage' limiter has triggered five times in five hours. The heat pump will shut down.
YesYes
14
EVE Ex valve will not close
PartlyYes
15
DHW temperature: DHW heating blocked until 22:00 h if set DHW temperature not reached within 'MAX DHW HTG DUR.'; retried, then blocked until 22:00 next day.
YesYes
16
Inverter communication fault
PartlyYes
17
Defrost time exceeded: The evaporator is not defrosted within the defined period; after ten successive occurrences the heat pump is blocked.
YesYes
18
Heating circuit pressure sensor: The heating circuit pressure sensor is not providing a plausible signal.
PartlyYes
19
Defrost duration of cross-countercurrent heat exchanger: Defrosting not completed after the defined time; fault displayed until defrost completes.
PartlyYes
20
Solar sensor: The solar circuit pump is not being switched.
PartlyYes
21
Outside temperature sensor: The heating system runs constantly with the flow temperature for manual mode.
PartlyYes
22
Hot gas temperature sensor: The compressor is switched off at outside temperatures < -10 °C and condenser temperatures > 40 °C.
YesYes
23
Condenser temperature sensor: The compressor is stopped.
YesYes
24
Evaporator temperature sensor: The compressor is stopped.
YesYes
25
Compressor inlet temperature: Cooling mode is blocked.
Varies by modelYes
26
Return temperature sensor in heating circuit: Heating switches to flow-temperature control; solar heat amount cannot be calculated.
PartlyYes
27
Evaporator output temperature: Evaporator control of the heat pump is disabled.
PartlyYes
28
Flow temperature sensor in heating circuit: Heating switches to return-temperature control; booster heater output cannot be calculated.
PartlyYes
29
DHW temperature sensor: DHW heating is blocked.
Varies by modelYes
30
Software version
PartlyYes
31
RAM
PartlyYes
32
EEProm
PartlyYes
33
Extract air humidity sensor
PartlyYes
34
Flow sensor: Flow (rate) sensor fault.
Not statedYes
35
Min. flow, cooling: Refrigerant inlet pressure below threshold during cooling; heat pump locked out, restarts after idle period if temperature rises.
YesYes
36
Min. flow rate: For 2 hours the flow rate has been < 5 l/min; electric emergency/booster heater blocked.
YesYes
37
Min. water pressure: Heating overpressure below 0.05 MPa (0.5 bar) and minimum flow rate not achieved; electric emergency/booster heater blocked.
Varies by modelYes
40
Float switch, bottom panel: The heat pump and the ventilation are switched off.
YesYes
42
Excess temperature, compressor: The heat pump remains off.
YesYes
43
Low pressure too low: The compressor is switched off for several minutes.
YesYes
44
Low pressure too high: The compressor is switched off for several minutes.
YesYes
45
Low pressure not assigned: The compressor is switched off for several minutes.
YesYes
46
High pressure too low: The compressor is switched off for several minutes.
YesYes
47
High pressure too high: The compressor is switched off for several minutes.
YesYes
48
High pressure not assigned: The compressor is switched off for several minutes.
YesYes
50
Sensor on heat pump return: Control continues; solar and compressor heat amounts cannot be calculated.
NoYes
51
Sensor on heat pump flow: Control continues; compressor heat and booster heater output cannot be calculated.
NoYes
52
Sensor on condenser outlet: Control continues despite this fault.
NoYes
53
Extract air temperature sensor
PartlyYes
54
Integral temperature sensor
PartlyYes
55
Temperature sensor at the top of the cylinder
PartlyYes
56
Sensor in the second DHW cylinder
PartlyYes
57
Sensor to measure the oil sump temperature
PartlyYes
58
Differential pressure sensor: The appliance only defrosts under time control or when triggered by the low pressure sensor; continues to run.
NoYes
59
Differential pressure sensor, fan control
PartlyYes
60
Inverter fault
PartlyYes
8167
The heat pump type set with the rotary selector does not match the installed electronic assembly.
YesYes
8168
4-way diverter valve does not switch to cooling.
YesYes
8169
4-way diverter valve does not switch to heating.
YesYes
8170
Internal inverter errors (IPM current sampling error, DC bus, AC input overcurrent, AC input voltage sampling error, DSP/PFC communication error, heat sink sensor fault, DSP/MCU communication error).
YesYes
8176
Flow and return connections have been interchanged.
YesYes
8177
Evaporator cannot dissipate enough heat in cooling mode.
YesYes
8181
Multiple occurrence of fault ERR HD SENSOR.
YesYes
8182
Multiple occurrence of fault ERR ND SENSOR.
YesYes
8183
Multiple occurrence of fault SOA HD EXCEEDED.
YesYes
8184
Multiple occurrence of fault MAX HOT GAS.
YesYes
8185
Multiple occurrence of fault DEFROST or MIN FLOW COOL.
YesYes
8186
Multiple occurrence of fault INV H INV EXCESS CURRENT.
YesYes
8188
Multiple occurrence of fault 8168.
YesYes
8189
Multiple occurrence of fault 8169.
YesYes
8191
Multiple response of inverter overcurrent relay.
YesYes
8192
Multiple occurrence of fault INV H PFC EXCESS CURRENT.
YesYes
8193
Multiple occurrence of fault INV H INV EXCESS TEMP.
YesYes
8208
Multiple response of high pressure switch at inverter.
YesYes
8255
Major inverter fault: Input current limit
YesYes
8256
Major inverter fault: Output current limit
YesYes
8257
Major inverter fault: Phase loss
YesYes
8258
Major inverter fault: Power module
YesYes
8259
Major inverter fault: Mains voltage sensor
YesYes
8260
Major inverter fault: Motor power offset
YesYes
8261
Major inverter fault: PFC power offset
YesYes
8262
Major inverter fault: Measure motor inductance
YesYes
8263
Major inverter fault: Measure motor phase resistance
YesYes
8264
Major inverter fault: Restart
YesYes
8265
Major inverter fault: Motor excess current shutdown function
YesYes
8266
Major inverter fault: IGBT US short circuit
YesYes
8267
Major inverter fault: IGBT OS short circuit
YesYes
8268
Major inverter fault: Motor phases short circuit
YesYes
8269
Major inverter fault: SVM function
YesYes
8270
Major inverter fault: Fan inverter excess current
YesYes
8271
Major inverter fault: Fan SVM function
YesYes
8272
Major inverter fault: Fan DC excess voltage
YesYes
8273
Major inverter fault: Fan DC undervoltage
YesYes
8274
Major inverter fault: Fan inverter excess temperature
YesYes
8275
Major inverter fault: Fan rotor vector
YesYes
8276
Major inverter fault: Fan motor excess speed
YesYes
8277
Major inverter fault: Fan phase loss
YesYes
8278
Major inverter fault: Fan power module
YesYes
8279
Major inverter fault: Fan motor power offset
YesYes
8280
Major inverter fault: Fan measure motor inductance
YesYes
8281
Major inverter fault: Fan measure motor phase resistance
YesYes
8282
Major inverter fault: Fan motor excess current shutdown function
YesYes
8283
Major inverter fault: Fan IGBT US short circuit
YesYes
8284
Major inverter fault: Fan IGBT OS short circuit
YesYes
8285
Major inverter fault: Fan motor phases short circuit
YesYes
8286
Minor inverter fault: Fan DC undervoltage
YesYes
8287
Minor inverter fault: Fan Modbus faulty
YesYes
8288
Minor inverter fault: Fan inverter low temperature
YesYes
8289
Minor inverter fault: Fan intermediate circuit initialisation
YesYes
8290
Minor inverter fault: Fan central fault 1
YesYes
8291
Low relevance communication objects have been incorrectly transferred repeatedly between the IWS and inverter (fan section).
YesYes
8292
High relevance communication objects have been incorrectly transferred repeatedly between the IWS and inverter (fan section).
YesYes
8293
ERR T VER EIN IWS: sensor value of the evaporator inlet temperature sensor outside the permissible range.
YesYes
8294
Minor inverter fault: Fan mains undervoltage
YesYes
8295
Minor inverter fault: Fan motor excess temperature
YesYes
8296
Major inverter fault: PFC excess current shutdown function
YesYes
8297
Minor inverter fault: Inverter temperature control
YesYes
8298
Minor inverter fault: Input current control
YesYes
8299
Major inverter fault: High pressure sensor range undershot
YesYes
8300
Major inverter fault: Compressor type configuration
YesYes
8301
Major inverter fault: High pressure sensor configuration
YesYes
10002
Compressor or starting contactor stuck.
YesYes
10003
The minimum low pressure limiter has been triggered.
YesYes
10004
The high pressure switch has responded.
YesYes
10005
The low pressure switch has been triggered.
YesYes
10006
The minimum mean pressure limiter has been triggered.
YesYes
10013
The minimum low pressure (< 0.9 bar absolute) limiter has been triggered.
YesYes
10015
The frost stat has been triggered in defrost mode.
YesYes
10023
High pressure sensor has exceeded the limit.
YesYes
10024
Hot gas temperature has exceeded limit.
YesYes
10025
Sensor value of the "high pressure sensor" outside the permissible range.
YesYes
10027
High pressure does not increase significantly above low pressure following compressor startup and a delay time.
YesYes
10028
Superheating of the refrigerant at the evaporator discharge or the compressor intake for too long below the permissible limit.
YesYes
10029
Unexpectedly high deviation of the expansion valve opening from the pre-control characteristic
YesYes
10034
Flow rate measurement incorrect.
YesYes
10042
Sensor value of the "condenser discharge sensor" outside the permissible range
YesYes
10047
The low pressure switch has been triggered in defrost operation.
YesYes
10048
The low pressure limiter has been triggered in cooling operation.
YesYes
10049
The frost protection pressure sensor has responded.
YesYes
10099
Sensor value of the "oil sump temperature sensor" outside the permissible range
YesYes
10108
Low supply voltage on FES
PartlyYes
10115
Incorrect communication with the FES.
PartlyYes
10227
Maximum number of CRC errors detected.
PartlyYes
10228
Error in communication with real time clock (RTC).
PartlyYes
10495
It was not possible to build up a sufficient flow rate to start the cooling operation.
YesYes
10500
An attempt to deactivate the charging pump to test the heat pump safety functions has failed. This may lead to a pressure drop in the heating circuit. It is possible to continue operating the system.
YesYes
10503
The safety assembly of the heat pump has triggered a gas warning.
YesYes
10511
Fan failure detected (no speed). A voltage reset for the fan was triggered.
PartlyYes
20012
Outlet limiter for high pressure compressor has been triggered.
YesYes
20014
Outlet limiter for low pressure compressor has been triggered.
YesYes
20022
Start limiter – fault for high pressure compressor has been triggered.
YesYes
20033
Minimum flow temperature not reached; switching point 6.5 °C.
YesYes
20035
Limiter for power interruption to inverter of low pressure compressor has been triggered.
PartlyYes
20036
Temperature limiter for inverter of low pressure compressor has been triggered.
PartlyYes
20037
Rotor stalled limiter for low pressure compressor has been triggered.
PartlyYes
20038
Start limiter – fault for low pressure compressor has been triggered.
YesYes
20039
Limiter for power failure to inverter of high pressure compressor has been triggered.
PartlyYes
20040
Temperature limiter for inverter of high pressure compressor has been triggered.
PartlyYes
20041
Rotor stalled limiter for high pressure compressor has been triggered.
PartlyYes
20045
Deviation between set and actual compressor speed values for a defined period of time (low pressure compressor in the case of two compressors)
YesYes
20046
Deviation between set and actual compressor speed values for a defined period of time (high pressure compressor in the case of two compressors)
YesYes
20050
Temperature limiter for minimum heat source flow temperature has tripped.
YesYes
20051
Temperature limiter for minimum heat source return temperature has tripped.
YesYes
20057
Major inverter fault: Inverter IGBT excess current
YesYes
20058
Major inverter fault: PFC IGBT excess current
YesYes
20059
Major inverter fault: DC link excess voltage
YesYes
20060
Major inverter fault: DC link undervoltage
YesYes
20061
Major inverter fault: AC input excess voltage
YesYes
20062
Major inverter fault: AC input undervoltage
YesYes
20063
Major inverter fault: Voltage differences between the three input phases
YesYes
20064
Major inverter fault: Desaturation
YesYes
20065
Major inverter fault: Inverter IGBTs excess temperature
YesYes
20066
Major inverter fault: PFC IGBTs excess temperature.
YesYes
20067
Major inverter fault: Rotor does not turn as expected.
YesYes
20068
Major inverter fault: Arithmetic fault in the measuring and analysis process
YesYes
20069
Major inverter fault: Input relay open
YesYes
20070
Major inverter fault: Current differences between the three inverter IGBTs
YesYes
20071
Major inverter fault: Current differences between the three PFC IGBTs
YesYes
20072
Major inverter fault: EEPROM error
YesYes
20073
Major inverter fault: Excess motor speed
YesYes
20074
Minor inverter fault: DC link undervoltage
YesYes
20075
Minor inverter fault: Torque limit reached
YesYes
20076
Minor inverter fault: Modbus communication malfunctioning
YesYes
20077
Minor inverter fault: Compressor scroll excess temperature
YesYes
20078
Minor inverter fault: Compressor motor excess temperature
YesYes
20079
Minor inverter fault: Switching circuit excess temperature
YesYes
20080
Minor inverter fault: Inverter IGBTs excess temperature
YesYes
20081
Minor inverter fault: PFC IGBTs excess temperature
YesYes
20084
Minor inverter fault: Temperature differences between the three inverter IGBTs
YesYes
20085
Minor inverter fault: Temperature differences between the three PFC IGBTs
YesYes
20091
Minor inverter fault: Communication disrupted between analogue/digital converter and auxiliary processor
YesYes
20093
Low relevance communication objects have been incorrectly transferred repeatedly between the IWS and inverter.
YesYes
20095
INV major fault central fault 1
YesYes
20096
INV major fault central fault 2
YesYes
20097
INV minor fault central fault 1
YesYes
20098
INV minor fault central fault 2
YesYes
20100
Low pressure below SOA low pressure limit for impermissible length of time.
YesYes
20101
Low pressure above SOA low pressure limit for impermissible length of time.
YesYes
20102
SOA range exceeded
YesYes
20103
High pressure below SOA high pressure limit for impermissible length of time.
YesYes
20104
High pressure exceeds SOA HD limit for impermissible length of time.
YesYes
20105
SOA range exceeded
YesYes
20135
Major inverter fault: Input current limitation
YesYes
20136
Major inverter fault: Output current limitation
YesYes
20137
Major inverter fault: Phase loss
YesYes
20138
Major inverter fault: Power module
YesYes
20139
Major inverter fault: Mains power supply sensor
YesYes
20140
Major inverter fault: Motor current offset
YesYes
20141
Major inverter fault: PFC current offset
YesYes
20142
Major inverter fault: Motor inductance measurement
YesYes
20143
Major inverter fault: Motor phase resistance measurement
YesYes
20144
Major inverter fault: Restart
YesYes
20145
Major inverter fault: Motor excess current shutdown function
YesYes
20146
Major inverter fault: IGBT US short circuit
YesYes
20147
Major inverter fault: IGBT OS short circuit
YesYes
20148
Major inverter fault: Motor phase short circuit
YesYes
20149
Major inverter fault: SVM function
YesYes
20150
Major inverter fault: Fan inverter excess current
YesYes
20151
Major inverter fault: Fan SVM function
YesYes
20152
Major inverter fault: Fan DC excess voltage
YesYes
20153
Major inverter fault: Fan DC excess voltage
YesYes
20154
Major inverter fault: Fan inverter excess temperature
YesYes
20155
Major inverter fault: Fan rotor vector
YesYes
20156
Major inverter fault: Fan motor excess speed
YesYes
20157
Major inverter fault: Fan phase loss
YesYes
20158
Major inverter fault: Fan power module
YesYes
20159
Major inverter fault: Fan motor current offset
YesYes
20160
Major inverter fault: Fan motor inductance measurement
YesYes
20161
Major inverter fault: Fan motor phase resistance measurement
YesYes
20162
Major inverter fault: Fan motor excess current shutdown function
YesYes
20163
Major inverter fault: Fan IGBT US short circuit
YesYes
20164
Major inverter fault: Fan IGBT OS short circuit
YesYes
20165
Minor inverter fault: Fan DC undervoltage
YesYes
20166
Minor inverter fault: Fan Modbus is faulty
YesYes
20167
Minor inverter fault: Inverter fan below temperature
YesYes
20168
Minor inverter fault: Fan DC link initialisation
YesYes
20169
Minor inverter fault: Fan central fault 1
YesYes
20170
Low relevance communication objects have been incorrectly transferred repeatedly between the IWS and inverter (fan section).
YesYes
20171
High relevance communication objects have been incorrectly transferred repeatedly between the IWS and inverter (fan section).
YesYes
20226
Major inverter fault: Fan motor phase short circuit
YesYes
20230
Minor inverter fault: Fan mains undervoltage
YesYes
20231
Minor inverter fault: Fan motor excess temperature
YesYes
20232
Major inverter fault: PFC excess current shutdown function
YesYes
20233
Minor inverter fault: Temperature control inverter
YesYes
20234
Minor inverter fault: Input current control
YesYes
20235
Major inverter fault: High pressure sensor range undershot
YesYes
20236
Major inverter fault: Compressor type configuration
YesYes
20237
Major inverter fault: High pressure sensor configuration
YesYes
20238
Limiter ND frost protection (source side)
YesYes
20240
The minimum overheating value of the oil sump compared to the condensation temperature for the monitoring time was permanently undershot.
YesYes
20241
Update completed successfully
NoNo
20242
Update completed successfully
NoNo
20243
Update completed successfully
NoNo
20244
Update failed
PartlyYes
20245
Update failed
PartlyYes
20246
Update failed
PartlyYes
20247
Compression chamber, limit value exceeded
YesYes
20248
Safety pressure cell has tripped.
YesYes
20249
New HP-ID type detected
NoNo
20277
Major inverter fault: Inverter extract air fan excess current
YesYes
20278
Major inverter fault: Extract air fan SVM function
YesYes
20279
Major inverter fault: Extract air fan DC excess voltage
YesYes
20281
Major inverter fault: Inverter extract air fan excess temperature
YesYes
20282
Major inverter fault: Extract air fan rotor vector
YesYes
20283
Major inverter fault: Extract air fan motor excess speed
YesYes
20284
Major inverter fault: Extract air fan phase loss
YesYes
20285
Major inverter fault: Extract air fan power module
YesYes
20286
Major inverter fault: Extract air fan motor current offset
YesYes
20288
Major inverter fault: Extract air fan motor phase resistance measurement
YesYes
20289
Major inverter fault: Extract air fan motor excess current shutdown function
YesYes
20290
Major inverter fault: Extract air fan IGBT US short circuit
YesYes
20291
Major inverter fault: Extract air fan IGBT OS short circuit
YesYes
20293
Minor inverter fault: Extract air fan Modbus faulty
YesYes
20294
Minor inverter fault: Inverter extract air fan below temperature
YesYes
20295
Minor inverter fault: Extract air fan DC link initialisation
YesYes
20296
Major inverter fault: Extract air fan motor phase short circuit
YesYes
20297
Minor inverter fault: Extract air fan motor excess temperature
YesYes
20298
Major inverter fault: Inverter supply air fan excess current
YesYes
20299
Major inverter fault: Supply air fan SVM function
YesYes
20300
Major inverter fault: Supply air fan DC excess voltage
YesYes
20302
Major inverter fault: Inverter supply air fan excess temperature
YesYes
20303
Major inverter fault: Supply air fan rotor vector
YesYes
20304
Major inverter fault: Supply air fan motor excess speed
YesYes
20305
Major inverter fault: Supply air fan phase loss
YesYes
20306
Major inverter fault: Supply air fan power module
YesYes
20307
Major inverter fault: Supply air fan motor current offset
YesYes
20308
Major inverter fault: Central fault 3
YesYes
20309
Major inverter fault: Supply air fan motor phase resistance measurement
YesYes
20310
Major inverter fault: Supply air fan motor excess current shutdown function
YesYes
20311
Major inverter fault: Supply air fan IGBT US short circuit
YesYes
20312
Major inverter fault: Supply air fan IGBT OS short circuit
YesYes
20313
Major inverter fault: Fan central fault 1
YesYes
20314
Minor inverter fault: Supply air fan Modbus faulty
YesYes
20315
Minor inverter fault: Inverter supply air fan below temperature
YesYes
20316
Minor inverter fault: Supply air fan DC link initialisation
YesYes
20317
Major inverter fault: Supply air fan motor phase short circuit
YesYes
20318
Minor inverter fault: Supply air fan motor excess temperature
YesYes
20329
Minor inverter fault: Extract air fan central fault 1
YesYes
20334
Minor inverter fault: Supply air fan central fault 1
YesYes
20371
Major inverter fault: Extract air fan central fault 1
PartlyYes
20376
Major inverter fault: Supply air fan central fault 1
PartlyYes
20383
Low relevance communication objects have been incorrectly transferred repeatedly between the IWS and inverter (extract air fan).
YesYes
20384
High relevance communication objects have been incorrectly transferred repeatedly between the IWS and inverter (extract air fan).
YesYes
20386
Low relevance communication objects have been incorrectly transferred repeatedly between the IWS and inverter (supply air fan).
YesYes
20387
High relevance communication objects have been incorrectly transferred repeatedly between the IWS and inverter (supply air fan).
YesYes
20420
Major inverter fault, compressor module: Short circuit motor phase (LeakageError)
YesYes
20421
Major inverter fault, compressor module: Communication error between KV5 and KV4 (Intercom)
YesYes
20423
Major inverter fault, compressor module: Fan on evaporator not turning (FanNotTurning).
YesYes
20424
Major inverter fault, compressor module: Short circuit motor module KV4 fan (KV4IPMotorShortCircuit)
YesYes
20426
Major inverter fault, compressor module: PFC temperature implausible (PFCTempUnplausible)
YesYes
20427
Major inverter fault, compressor module: PFC excess temperature (>100 °C) (PFCOvertemp)
YesYes
20428
Major inverter fault, compressor module: PFC faulty (PFCUtrip, PFCDriverShutdown)
YesYes
20429
Major inverter fault, compressor module: Min. one DC-Link capacitor short circuit (DCLinkCapShort)
YesYes
20430
Major inverter fault, evaporator fan: Short circuit motor phase (LeakageError)
YesYes
20431
Major inverter fault, evaporator fan: Communication fault between KV5 and KV4 (intercom)
YesYes
20432
Major inverter fault, evaporator fan: Mains voltage interrupted (MainsInterrupted).
YesYes
20433
Major inverter fault, evaporator fan: DC link voltage too low (DCLinkVoltageLow)
YesYes
20435
Major inverter fault, evaporator fan: Fan on evaporator not turning (FanNotTurning).
YesYes
20436
Major inverter fault, extract air fan: Short circuit motor phase (LeakageError)
YesYes
20437
Major inverter fault, extract air fan: Communication fault between KV5 and KV4 (intercom)
YesYes
20438
Major inverter fault, extract air fan: Mains voltage interrupted (MainsInterrupted).
YesYes
20439
Major inverter fault, extract air fan: DC link voltage too low (DCLinkVoltageLow)
YesYes
20441
Major inverter fault, supply air fan: Short circuit motor phase (LeakageError)
YesYes
20442
Major inverter fault, supply air fan: Communication fault between KV5 and KV4 (intercom)
YesYes
20443
Major inverter fault, supply air fan: Mains voltage interrupted (MainsInterrupted).
YesYes
20444
Major inverter fault, supply air fan: DC link voltage too low (DCLinkVoltageLow)
YesYes
20458
Major inverter fault: Central fault 4
YesYes
20459
Major inverter fault: Fan central fault 2
YesYes
20460
Major inverter fault: Extract air fan central fault 2
YesYes
20461
Major inverter fault: Supply air fan central fault 2
YesYes
20504
IWS update performed
NoNo
20505
ILS update performed
NoNo
20506
IWS update failed
YesYes
20507
ILS update failed
PartlyYes
20532
The flow or return temperature exceeds the set limits.
PartlyYes
30002
Compressor or starting contactor stuck.
YesYes
30007
The minimum brine pressure limiter has been triggered.
PartlyYes
30008
The HP type DIP switch of the IWS is set incorrectly.
YesYes
30009
Sensor value of the "mean pressure sensor" outside the permissible range
YesYes
30010
For heat pumps with one compressor and intermediate injection: sensor value of the "injection temperature sensor" outside the permissible range. For heat pumps with two compressors: sensor value of the "suction gas temperature sensor for high pressure compressor" outside the permissible range
YesYes
30011
Sensor value of the "suction gas temperature sensor for low pressure compressor" outside theconnectors, a permissible range
YesYes
30016
Sensor value of the "hot gas temperature sensor" outside the permissible range
YesYes
30017
Sensor value of the "evaporator temperature sensor" outside the permissible range
YesYes
30018
Sensor value of the "cooling sensor/recuperator sensor" outside the permissible range
YesYes
30019
Sensor value of the "outside temperature sensor" outside the permissible range
YesYes
30020
Sensor value of the "frost protection temperature sensor" outside the permissible range
YesYes
30021
Sensor value of the "injection temperature sensor" outside the permissible range
YesYes
30025
Sensor value of the "high pressure sensor" outside the permissible range
YesYes
30026
Sensor value of the "low pressure sensor" outside the permissible range
YesYes
30031
Sensor value of the "flow temperature sensor" outside the permissible range
YesYes
30032
Sensor value of the "return temperature sensor" outside the permissible range
YesYes
30042
Sensor value of the "condenser discharge sensor" outside the permissible range
YesYes
30043
Sensor value of the "exhaust air temperature sensor" outside the permissible range
YesYes
30044
Sensor value of the "differential pressure sensor" outside the permissible range
YesYes
30052
Brine pressure switch has responded.
YesYes
30053
At least two assemblies with the same bus ID are present on the bus system.
YesYes
30054
The thermistor protection relay for the compressor has been triggered.
YesYes
30056
Oil compensation valve does not open/close.
YesYes
30063
Major inverter fault: Voltage differences between the three input phases.
YesYes
30082
Minor inverter fault: Communication between signal processor and main processor is faulty.
YesYes
30083
Minor inverter fault: Communication between signal processor and main processor is faulty.
YesYes
30086
Minor inverter fault: Temperature sensor fault, scroll temperature below the permissible range.
YesYes
30087
Minor inverter fault: Temperature sensor fault, motor temperature below the permissible range.
YesYes
30088
Minor inverter fault: Temperature sensor fault, internal switching circuit temperature below the permissible range.
YesYes
30089
Minor inverter fault: Temperature sensor fault, inverter IGBTs below the permissible range.
YesYes
30090
Minor inverter fault: Temperature sensor fault, PFC IGBTs below the permissible range.
YesYes
30092
Minor inverter fault: Inverter fault limit has been achieved and inverter was interlocked.
YesYes
30094
High relevance communication objects have been incorrectly transferred repeatedly between the IWS and inverter.
YesYes
30099
Sensor value of the "oil sump temperature sensor" outside the permissible range
YesYes
30106
The defined minimum source temperature was not reached.
YesYes
30107
Incorrect communication with the WPM.
PartlyYes
30110
Sensor value of the "FE 7" outside the permissible range
PartlyYes
30111
FES version conflict
PartlyYes
30112
WPE version conflict
PartlyYes
30113
FET version conflict
PartlyYes
30114
WPM version conflict
PartlyYes
30117
Limiter communication interruption IWS/CWS
YesYes
30124
The minimum flow rate was undershot during defrosting.
YesYes
30125
MFG sensor value of the "HP return temperature" outside the permissible range.
YesYes
30126
MFG sensor value of the "HP flow temperature" outside the permissible range.
YesYes
30127
MFG sensor value of the "flow rate" outside the permissible range.
YesYes
30128
Incorrect communication with the HP return temperature sensor in the MFG.
YesYes
30129
Incorrect communication with the HP flow temperature sensor in the MFG.
YesYes
30130
Incorrect communication with the heating circuit flow rate sensor in the MFG.
YesYes
30133
Heat pump fan speed could not be detected.
YesYes
30172
Float switch has tripped.
YesYes
30173
IWS sensor value of the "heat source return temperature" outside the permissible range
YesYes
30174
IWS sensor value of the "heat source flow temperature" outside the permissible range
YesYes
30175
MFG sensor value of the "HP return temperature" outside the permissible range
PartlyYes
30176
MFG sensor value of the "WP flow temperature" outside the permissible range
PartlyYes
30177
MFG sensor value of the "NHZ flow temperature" outside the permissible range
PartlyYes
30178
MFG sensor value of the "DHW temperature" outside the permissible range
PartlyYes
30186
The heating circuit pump on the MFG cannot be switched.
PartlyYes
30188
The 3-way diverter valve in the MFG cannot be switched.
PartlyYes
30189
The emergency/auxiliary heater in the MFG cannot be switched.
PartlyYes
30190
Incorrect communication with the HP return temperature sensor in the MFG.
PartlyYes
30191
Incorrect communication with the HP flow temperature sensor in the MFG.
PartlyYes
30192
Incorrect communication with the NHZ flow sensor in the MFG.
PartlyYes
30193
Incorrect communication with the DHW temperature sensor in the MFG.
PartlyYes
30196
Incorrect communication with the heating circuit flow rate sensor in the MFG.
PartlyYes
30197
Incorrect communication with the brine circuit flow rate sensor in the MFG.
PartlyYes
30198
Incorrect communication with the heating circuit pressure sensor in the MFG.
PartlyYes
30199
Incorrect communication with the brine pressure sensor in the MFG.
PartlyYes
30201
Incorrect communication with the heating circuit pump in the MFG.
PartlyYes
30202
Incorrect communication with the brine pump in the MFG.
PartlyYes
30203
Incorrect communication with the 3-way diverter valve in the MFG.
PartlyYes
30204
Incorrect communication with the emergency/ auxiliary heater in the MFG.
PartlyYes
30205
Incorrect communication with the MFG.
PartlyYes
30206
Sensor value of the "current sensor" outside the permissible range.
YesYes
30207
Sensor value of "outside temperature sensor" outside the permissible range
PartlyYes
30208
Sensor value of "buffer temperature sensor (heating circuit sensor 1)" outside the permissible range
PartlyYes
30209
Sensor value of "flow temperature sensor" outside the permissible range
PartlyYes
30210
Sensor value of "heating circuit sensor 2" outside the permissible range
PartlyYes
30211
Sensor value of "heating circuit sensor 3" outside the permissible range
PartlyYes
30212
Sensor value of "DHW cylinder sensor" outside the permissible range
PartlyYes
30213
Sensor value of "source sensor" outside the permissible range
PartlyYes
30214
Sensor value of "heat generator 2" outside the permissible range
PartlyYes
30215
Sensor value of "flow cooling sensor" outside the permissible range
PartlyYes
30216
Sensor value of "DHW circulation temperature sensor" outside the permissible range
PartlyYes
30217
Sensor value of "swimming pool sensor, primary" outside the permissible range
PartlyYes
30218
Sensor value of "swimming pool sensor, secondary" outside the permissible range
PartlyYes
30219
Sensor value of "heating circuit sensor 4" outside the permissible range
PartlyYes
30220
Sensor value of "heating circuit sensor 5" outside the permissible range
PartlyYes
30221
Sensor value of "DHW cylinder 2 sensor" outside the permissible range
PartlyYes
30222
Sensor value of "differential sensor 1.1" or "thermostat sensor 1" outside the permissible range
PartlyYes
30223
Sensor value of "differential sensor 1.2" outside the permissible range
PartlyYes
30224
Sensor value of "differential sensor 2.1" or "thermostat sensor 2" outside the permissible range
PartlyYes
30225
Sensor value of "differential sensor 2.2" outside the permissible range
PartlyYes
30229
Sensor value of "evaporator inlet temperature sensor" outside the permissible range
YesYes
30239
The heating circuit assigned in FEK 2 is not present in the WPM.
PartlyYes
30248
Safety pressure cell has tripped.
YesYes
30251
The brine pressure switch for minimum brine pressure has responded.
YesYes
30252
Sensor value of the "expansion valve inlet temperature sensor" outside the permissible range
YesYes
30397
Supply air temperature outside permissible range (ventilation)
PartlyYes
30398
Exhaust air temperature outside permissible range (ventilation)
PartlyYes
30399
Outdoor air temperature preheated beyond permissible range (ventilation)
PartlyYes
30403
Communication fault, fine dust sensor (ventilation)
PartlyYes
30404
SUP fan (no speed feedback) (ventilation)
PartlyYes
30405
EHA fan (no speed feedback) (ventilation)
PartlyYes
30406
Communication fault, outdoor air humidity and temperature SHT31 (ventilation)
PartlyYes
30407
Communication fault, extract air humidity and temperature SHT31 (ventilation)
PartlyYes
30408
Heating coil fault (temperature too low, SUP shutdown) (ventilation)
PartlyYes
30409
Heater contact triggered (ventilation)
PartlyYes
30410
Sensor voltage (ventilation)
PartlyYes
30457
Major inverter fault, compressor module: Second STO input open (stove /chimney contact)
YesYes
30467
Faulty temperature and humidity sensor in programming unit
PartlyYes
30468
Temperature limiter for maximum oil sump temperature has responded.
YesYes
30469
Faulty VOC sensor in programming unit
PartlyYes
30470
Internal fault, no V-ID entered in ventilation module
PartlyYes
30475
Sensor value of the "water pressure sensor" outside the permissible range.
PartlyYes
30479
Minimum water flow rate for activating auxiliary heater not reached
PartlyYes
30480
The system pressure is too low.
PartlyYes
30483
Auxiliary heater without power supply
PartlyYes
30488
Sensor value of the "ventilation" outside temperature sensor outside the permissible range
PartlyYes
30489
I2C sensor value for "Preheated outdoor air humidity" outside the permissible range
PartlyYes
30490
I2C sensor value for "Extract air temperature" outside the permissible range
PartlyYes
30491
I2C sensor value for "Extract air humidity" outside the permissible range
PartlyYes
30492
I2C sensor value of the "Supply air differential pressure sensor" outside the permissible range
PartlyYes
30493
I2C sensor value of the "Exhaust air differential pressure sensor" outside the permissible range
PartlyYes
30494
I2C sensor value of the "Extract air differential pressure sensor" outside the permissible range
PartlyYes
30497
Switching contact for the sacrificial anode has been triggered.
PartlyYes
30501
The safety valve cannot be moved during a function test.
YesYes
30502
When the safety valve is open, no water flow rate can be measured via the heat pump during a function test.
YesYes
30503
The safety assembly of the heat pump has triggered a gas warning.
YesYes
30508
Double addressing of the EBPE detected.
YesYes
30509
It was not possible to establish communication between IWS and EBPE.
YesYes
30512
Safety prompts not supported.
YesYes
30513
Function test could not be performed.
YesYes
30514
A mechanical ventilation fan is not achieving its set flow rate.
PartlyYes
30515
No HP ID selected.
PartlyYes
30516
No hydraulic ID selected.
PartlyYes
30533
Minimum flow rate not present at compressor start.
PartlyYes
40481
System pressure low.
PartlyYes
40482
System pressure too high.
PartlyYes
50002
Repeated instances of message number X-0002 has led to heat pump interlock.
YesYes
50003
Repeated instances of message number X-0003 has led to heat pump interlock.
YesYes
50004
Repeated instances of message number X-0004 has led to heat pump interlock.
YesYes
50006
Repeated instances of message number X-0006 has led to heat pump interlock.
YesYes
50008
The HP type DIP switch of the IWS is set incorrectly.
YesYes
50013
Repeated instances of message number X-0013 has led to heat pump interlock.
YesYes
50015
Repeated instances of message number X-0015 has led to heat pump interlock.
YesYes
50026
Sensor value of "low pressure sensor" outside the permissible range
YesYes
50027
Repeated instances of message number X-0027 has led to heat pump interlock.
YesYes
50028
Repeated instances of message number X-0028 has led to heat pump interlock.
YesYes
50029
Repeated instances of message number X-0029 has led to heat pump interlock.
YesYes
50034
Repeated instances of message number X-0034 has led to heat pump interlock.
YesYes
50047
Repeated instances of message number X-0047 has led to heat pump interlock.
YesYes
50048
Repeated instances of message number X-0048 has led to heat pump interlock.
YesYes
50049
Repeated instances of message number X-0049 has led to heat pump interlock.
YesYes
50133
Heat pump fan speed could not be detected.
YesYes
50248
Repeated instances of message number X-0248 has led to heat pump interlock.
YesYes
50250
Temperature switch on compressor case has tripped.
YesYes
50400
Communication fault, supply air differential pressure (ventilation)
YesYes
50401
Communication fault, exhaust air differential pressure (ventilation)
YesYes
50402
Communication fault, extract air differential pressure (ventilation)
YesYes
50411
OA preheated, ventilation Tmax exceeded (ventilation)
YesYes
50468
Repeated instances of message number X-0468 has led to heat pump interlock.
YesYes
50495
It was repeatedly not possible to build up a sufficient flow rate to start cooling operation.
YesYes
50496
Diverter valve has not switched. It is not possible to operate the heat pump in reverse mode.
YesYes
50501
Repeated instances of message number X-0501 has led to heat pump interlock.
YesYes
50502
Repeated instances of message number X-0502 has led to heat pump interlock.
YesYes
CENTRAL-FAULT
230 V signal not present at the IWS fault inputs 10 s after a controlled heat pump shutdown; red LED on IWS flashes.
YesYes
COMM-U-IWS-CSW
Limiter communication interruption IWS / CWS.
YesYes
COMMUNICATION-IWS-INV-H
High relevance communication objects repeatedly transferred incorrectly between IWS and inverter.
YesYes
COMMUNICATION-IWS-INV-N
Low relevance communication objects repeatedly transferred incorrectly between IWS and inverter.
YesYes
CONTACTOR-STUCK
Compressor or starting contactor stuck.
YesYes
DEFROST
During defrost the flow, return or frost-protection temperature fell below 10 °C (or flow rate too low, e.g. <10 l/min WPL 15, <15 l/min WPL 25).
YesYes
ERR-CURRENT
Value of the current sensor outside the permissible range.
YesYes
ERR-DEFROST
Multiple DEFROST faults within a defined compressor runtime (5 in 2 hours).
YesYes
ERR-EV-DIFF-PR
Sensor value of the differential pressure sensor outside the permissible range.
YesYes
ERR-FLOW-RATE
5 FLOW RATE faults in 24 hours of compressor runtime.
YesYes
ERR-HD-PRESSURE
5 faults (multiple responses) of the HIGH PRESSURE limiter within a defined compressor runtime.
YesYes
ERR-HD-SENSOR
Sensor value of the high pressure sensor outside the permissible range.
YesYes
ERR-K-LOW-IWS
Multiple REFRIGERANT LOW faults within a defined compressor runtime.
YesYes
ERR-K-OUTPUT
Multiple NO OUTPUT faults within a defined compressor runtime (5 in 2 hours).
YesYes
ERR-M-SUPERHEATING-IWS
Multiple MIN SUPERHEATING faults within a defined compressor runtime.
YesYes
ERR-MD-PRESSURE
Multiple MEAN PRESSURE faults within a defined compressor runtime.
YesYes
ERR-MD-SENSOR
Sensor value of the mean pressure sensor outside the permissible range.
YesYes
ERR-ND-COOLING
5 ND COOLING faults in 2 hours of compressor runtime.
YesYes
ERR-ND-DEFROST
5 ND DEFROST faults in 2 hours of compressor runtime.
YesYes
ERR-ND-PRESSURE
5 faults (multiple responses) of the LOW PRESSURE limiter within a defined compressor runtime (e.g. 2 hours).
YesYes
ERR-ND-SENSOR
Sensor value of the low pressure sensor outside the permissible range.
YesYes
ERR-NHZ-MFG
The electric emergency/booster heater in the MFG is faulty.
YesYes
ERR-OIL-COMPENSATION
Oil compensation valve does not open/close.
YesYes
ERR-PU-HZG-MFG
Error heating circuit pump MFG.
YesYes
ERR-T-AUS-IWS
Sensor value of the outside temperature sensor outside the permissible range.
YesYes
ERR-T-COOL-IWS
Cooling/recuperator sensor value outside permissible range.
YesYes
ERR-T-EIN-IWS
Sensor value of the injection temperature sensor outside the permissible range.
YesYes
ERR-T-EXHA-IWS
Sensor value of the exhaust air sensor outside the permissible range.
YesYes
ERR-T-FROS-IWS
Sensor value of the frost protection sensor outside the permissible range.
YesYes
ERR-T-HTG-IWS
Sensor value of the hot gas temperature sensor outside the permissible range.
YesYes
ERR-T-OIL-S-IWS
Sensor value of the oil sump temperature sensor outside the permissible range.
YesYes
ERR-T-RUE-IWS
Sensor value of the return sensor outside the permissible range.
YesYes
ERR-T-SUCT
Sensor value of the compressor inlet (suction gas) temperature sensor outside the permissible range.
YesYes
ERR-T-SUCT-VHD
Sensor value of the suction gas temperature sensor for high pressure compressor outside the permissible range.
YesYes
ERR-T-SUCT-VND
Sensor value of the suction gas temperature sensor for low pressure compressor outside the permissible range.
YesYes
ERR-T-VER-IWS
Sensor value of the evaporator temperature sensor outside the permissible range.
YesYes
ERR-T-VFL-IWS
Sensor value of the condenser outlet sensor outside the permissible range.
YesYes
ERR-T-VOR-IWS
Sensor value of the flow sensor outside the permissible range.
YesYes
ERR-VALVE-MFG
Error 3-way diverter valve MFG.
YesYes
EXV-LP-2
3 LP 2 faults in 10 minutes of compressor runtime have occurred.
YesYes
FLOW-RATE
Flow rate monitoring (from heating output, flow and return temperature) has responded.
YesYes
FROST-PROTECTION
The frost protection pressure sensor has responded (brine/source side).
YesYes
HD-SENSOR-MAX
The high pressure sensor maximum limit has been reached.
YesYes
HEXADECIMAL-SWITCH
Heat pump type DIP switch on the IWS set incorrectly (e.g. for cascade mode).
YesYes
HIGH-PRESSURE
The high pressure limiter has responded (switching point e.g. 30 bar abs type 1; 42 bar type 3; 29/39 bar type 4).
YesYes
I-INV-V-HD
Limiter for power failure to inverter of high pressure compressor has been triggered.
YesYes
I-INV-V-ND
Limiter for power interruption to inverter of low pressure compressor has been triggered.
YesYes
INV-H-AC-EXCESS-VOLTAGE
Major inverter fault: AC input excess voltage.
YesYes
INV-H-AC-UNDERVOLTAGE
Major inverter fault: AC input undervoltage.
YesYes
INV-H-AC-VOLTAGE-BALANCE
Major inverter fault: Voltage differences between the three input phases.
YesYes
INV-H-ARITHMETIC
Major inverter fault: Arithmetic fault in the measuring and analysis process.
YesYes
INV-H-CENTRAL-FAULT-1
Major inverter fault: INV major fault central fault 1.
YesYes
INV-H-CENTRAL-FAULT-2
Major inverter fault: INV major fault central fault 2.
YesYes
INV-H-DC-EXCESS-VOLTAGE
Major inverter fault: DC intermediate circuit excess voltage.
YesYes
INV-H-DC-UNDERVOLTAGE
Major inverter fault: DC intermediate circuit undervoltage.
YesYes
INV-H-DESATURATION
Major inverter fault: Desaturation.
YesYes
INV-H-INPUT-RELAY-OPEN
Major inverter fault: Input relay open.
YesYes
INV-H-INV-CURRENT-BALANCE
Major inverter fault: Current differences between the three inverter IGBTs.
YesYes
INV-H-INV-EXCESS-CURRENT
Major inverter fault: Inverter IGBT excess current.
YesYes
INV-H-INV-EXCESS-TEMP
Major inverter fault: Inverter IGBTs excess temperature.
YesYes
INV-H-MOTOR-EXCESS-SPEED
Major inverter fault: Motor excess speed.
YesYes
INV-H-PFC-CURRENT-BALANCE
Major inverter fault: Current differences between the three PFC IGBTs.
YesYes
INV-H-PFC-EXCESS-CURRENT
Major inverter fault: PFC IGBT excess current.
YesYes
INV-H-PFC-EXCESS-TEMP
Major inverter fault: PFC IGBTs excess temperature.
YesYes
INV-H-ROTOR-VECTOR
Major inverter fault: Rotor does not turn as expected.
YesYes
INV-H-SELV-RANGE-EXT
Major inverter fault: LV range exceeded.
YesYes
INV-N-ADC-COMM
Minor inverter fault: Communication between analogue/digital converter and auxiliary processor is faulty.
YesYes
INV-N-BOARD-EXCESS-TEMP
Minor inverter fault: Switching circuit excess temperature.
YesYes
INV-N-BOARD-LOW-TEMP
Minor inverter fault: Temperature sensor fault, internal switching circuit temperature below the permissible range.
YesYes
INV-N-CENTRAL-FAULT-1
Minor inverter fault: INV minor fault central fault 1.
YesYes
INV-N-CENTRAL-FAULT-2
Minor inverter fault: INV minor fault central fault 2.
YesYes
INV-N-COMM-AFTER-DSP
Minor inverter fault: Communication between signal processor and main processor is faulty.
YesYes
INV-N-DC-UNDERVOLTAGE
Minor inverter fault: DC intermediate circuit undervoltage.
YesYes
INV-N-DSP-AFTER-COMM
Minor inverter fault: Communication between signal processor and main processor is faulty.
YesYes
INV-N-FAULT-LIMIT-FATAL
Minor inverter fault: Inverter fault limit has been achieved and inverter was interlocked.
YesYes
INV-N-INV-EXCESS-TEMP
Minor inverter fault: Inverter IGBTs excess temperature.
YesYes
INV-N-INV-LOW-TEMPERATURE
Minor inverter fault: Temperature sensor fault, inverter IGBTs below the permissible range.
YesYes
INV-N-INV-TEMP-BALANCE
Minor inverter fault: Temperature differences between the three inverter IGBTs.
YesYes
INV-N-MODBUS-ERROR
Minor inverter fault: Modbus communication is faulty.
YesYes
INV-N-MOTOR-EXCESS-TEMP
Minor inverter fault: Compressor motor excess temperature.
YesYes
INV-N-MOTOR-LOW-TEMP
Minor inverter fault: Temperature sensor fault, motor temperature below the permissible range.
YesYes
INV-N-PFC-EXCESS-TEMP
Minor inverter fault: PFC IGBT excess temperature.
YesYes
INV-N-PFC-LOW-TEMPERATURE
Minor inverter fault: Temperature sensor fault, PFC IGBTs below the permissible range.
YesYes
INV-N-PFC-TEMP-BALANCE
Minor inverter fault: Temperature differences between the three PFC IGBTs.
YesYes
INV-N-SCROLL-EXCESS-TEMP
Minor inverter fault: Compressor scroll excess temperature.
YesYes
INV-N-SCROLL-LOW-TEMP
Minor inverter fault: Temperature sensor fault, scroll temperature below the permissible range.
YesYes
INV-N-TORQUE-LIMIT
Minor inverter fault: Torque limit achieved.
YesYes
IWS-RED-LED-FLASHING
Red LED on the IWS (integral heat pump controller) flashes: single fault; appliance shut down and restarts after 10 minutes.
YesYes
IWS-RED-LED-ON
Red LED on the IWS illuminates: more than 5 faults within 2 hours run; appliance shut down permanently until reset.
YesYes
LOW-PRESSURE
The low pressure sensor/minimum low pressure limiter has responded (switching point depends on HP type, e.g. 1.2 bar abs within 60 s for type 1; <2 bar for 10 s type 3; <1.0 bar for 240 s type 4).
YesYes
LP-2
Low pressure < 0.9 bar absolute within 5 seconds.
YesYes
MAX-HOT-GAS
Hot gas temperature exceeded limit (125 °C types 1/2; 140 °C types 3/4).
YesYes
MEAN-PRESSURE
Minimum mean pressure limiter triggered (e.g. below 2 bar for 10 s / 1.0 bar for 240 s).
YesYes
MIN-FLOW-COOL
Minimum flow temperature not reached in cooling; switching point 6.5 °C.
YesYes
MIN-SOURCE
The defined minimum source temperature was not reached.
YesYes
MIN-SUPERHEATING
Superheating at the evaporator outlet / compressor inlet below the permissible minimum for too long.
YesYes
ND-COOLING
Low pressure sensor responded in cooling mode (switching point 4 bar abs within 5 s).
YesYes
ND-DEFROST
Low pressure sensor responded in defrost mode (switching point 2 bar abs within 10 s).
YesYes
NO-IWS-PARAM
Heat pump type was not transferred to the controller.
YesYes
NO-OUTPUT
High pressure does not rise significantly above low pressure after compressor start (e.g. HP < LP + 2 bar within 30/120 s).
YesYes
OUTL-INV-V-HD
Outlet limiter for high pressure compressor has been triggered.
YesYes
OUTL-INV-V-ND
Outlet limiter for low pressure compressor has been triggered.
YesYes
REFRIGERANT-LOW
Unexpectedly high deviation of expansion valve opening from the pre-control characteristic (superheating high with valve opening above limit).
YesYes
ROTOR-KL-V-HD
Rotor stalled limiter for high pressure compressor has been triggered.
YesYes
ROTOR-KL-V-ND
Rotor stalled limiter for low pressure compressor has been triggered.
YesYes
SENSOR-BREAK-E-70
System fault: mixer sensor break.
PartlyYes
SENSOR-BREAK-E-71
System fault: source sensor break.
PartlyYes
SENSOR-BREAK-E-72
System fault: flow sensor break.
PartlyYes
SENSOR-BREAK-E-73
System fault: return sensor break.
PartlyYes
SENSOR-BREAK-E-75
System fault: outside temperature sensor break.
PartlyYes
SENSOR-BREAK-E-76
System fault: DHW sensor break.
PartlyYes
SENSOR-BREAK-E-77
System fault: heat source 2 (HS 2) sensor break.
PartlyYes
SENSOR-BREAK-E-80
System fault: remote control (sensor) break.
PartlyYes
SENSOR-BREAK-E-129
System fault: collector (solar) sensor break.
PartlyYes
SOA-HD-ALLOCATION
SOA range exceeded (high pressure allocation).
YesYes
SOA-HD-EXCEEDED
High pressure exceeds SOA high-pressure limit for impermissible length of time.
YesYes
SOA-HD-UNDERSHOT
High pressure below SOA high-pressure limit for impermissible length of time.
YesYes
SOA-ND-ALLOCATION
SOA range exceeded (low pressure allocation).
YesYes
SOA-ND-EXCEEDED
Low pressure exceeds SOA low-pressure limit for impermissible length of time.
YesYes
SOA-ND-UNDERSHOT
Low pressure below SOA low-pressure limit for impermissible length of time.
YesYes
SPEED-DEV-COMP-HD
Speed deviation between set and actual values of the high pressure compressor for a defined time.
YesYes
SPEED-DEV-COMP-ND
Speed deviation between set and actual compressor values for a defined time (low pressure compressor).
YesYes
START-F-V-ND
Start limiter fault for low pressure compressor has been triggered.
YesYes
START-INV-C-HP
Start limiter fault for high pressure compressor has been triggered.
YesYes
SUPERHEATING-INV-V-HD
Temperature limiter for inverter of high pressure compressor has been triggered.
YesYes
SUPERHEATING-INV-V-ND
Temperature limiter for inverter of low pressure compressor has been triggered.
YesYes
TO-MFG
MFG timeout.
YesYes
TO-NHZ-MFG
Incorrect communication of the electric emergency/booster heater in the MFG.
YesYes
TO-P-HK-MFG
Incorrect communication with the MFG (heating circuit pressure).
YesYes
TO-PU-HK-MFG
Incorrect communication between heating circuit pump and MFG.
YesYes
TO-T-VOR-NHZ-MFG
The flow sensor of the electric emergency/booster heater in the multifunction assembly (MFG) is faulty/timeout.
YesYes
TO-VALVE-MFG
Incorrect communication between 3-way diverter valve and MFG.
YesYes
TO-VOL-HK-MFG
Incorrect communication with the MFG (heating circuit flow rate).
YesYes