iDM Energiesysteme · No longer sold new in the UK. 171 codes across 1 product family, each taken from the manufacturer’s manuals. iDM Energiesysteme technical support ↗
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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.
171 codes
| Code | Meaning | Stops? | Homeowner check? |
|---|---|---|---|
| 020 | Heat pump flow maximum temperature: Heat pump flow temperature is above the set maximum temperature. | Yes | Yes |
| 021 | Heat pump flow minimum temperature: Heat pump flow temperature is below the set minimum temperature. | Yes | Yes |
| 022 | Low pressure fault: The low-pressure monitor has switched the heat pump off (< 3 times in 24 h). | Yes | Yes |
| 023 | Low pressure fault - lockout: The low-pressure monitor has switched the heat pump off (> 3 times in 24 h). The heat pump is no longer operated. After fault 023 the unit may be unlocked at most once! | Yes | Yes |
| 024 | High pressure fault: The high-pressure monitor has switched the heat pump off (< 3 times in 24 h). | Yes | Yes |
| 025 | High pressure fault - lockout: The high-pressure monitor has switched the heat pump off (> 3 times in 24 h). The heat pump is no longer operated. | Yes | Yes |
| 026 | Flow monitoring / pressure monitoring: The flow switch on groundwater systems has switched the heat pump off (< 3 times in 24 h). | Yes | Yes |
| 027 | Flow lockout / pressure monitoring - lockout: The flow switch on groundwater systems has switched the heat pump off (> 3 times in 24 h). The heat pump is no longer operated. | Yes | Yes |
| 028 | Soft starter 1 (see LED): Soft-starter fault (< 5 times in 24 h). The type of fault is indicated on the soft starter. | Yes | Yes |
| 029 | Soft starter 1 - lockout: Soft-starter fault (> 5 times in 24 h). The heat pump is no longer operated. | Yes | Yes |
| 030 | Motor protection heat source pump: The motor protection of the heat source (brine/well) pump has tripped (< 5 times in 24 h). | Yes | Yes |
| 031 | Motor protection heat source pump - lockout: The motor protection of the heat source pump has tripped (> 5 times in 24 h). The heat pump is no longer operated. | Yes | Yes |
| 032 | Maximum defrost time exceeded: The maximum defrost time was exceeded. | Not stated | Yes |
| 033 | Minimum condenser temperature undershot: The heat pump was switched off because the minimum condenser temperature was undershot. | Yes | Yes |
| 034 | Fan fault: Fault contact of the fan electronics has responded (< 3 times in 24 h). | Yes | Yes |
| 035 | Minimum heat storage temperature undershot: Heat storage (buffer) temperature required for defrosting was undershot. | Partly | Yes |
| 036 | Electric heating element overheating: Safety temperature limiter (STB) of the electric heater has tripped. | Partly | Yes |
| 037 | Charging pump fault: Fault contact of the charging pump has tripped. | Yes | Yes |
| 038 | Fan fault - lockout: Fault contact of the fan electronics has tripped (> 3 times in 24 h). The heat pump is no longer operated. | Yes | Yes |
| 042 | Hot gas temperature too low: Hot gas temperature is lower than condensing temperature + 10°C. Delay 7 min. | Yes | Yes |
| 043 | Hot gas temperature too low - lockout: The heat pump was switched off due to too low hot gas temperature (> 5 times in 24 h). | Yes | Yes |
| 044 | Flow monitoring heating side: The flow monitor on the heating side has responded. Flow is monitored in heating, cooling and defrost operation. | Yes | Yes |
| 046 | Hot gas temperature too high: Hot gas temperature is higher than 135°C (< 5 times in 24 h). | Yes | Yes |
| 047 | Hot gas temperature too high - lockout: The heat pump was switched off due to too high hot gas temperature (> 5 times in 24 h). The heat pump is no longer operated. | Yes | Yes |
| 050 | Dew point monitor responded: Dew point monitor has responded (flow temperature adjustment). | No | Yes |
| 051 | Dew point monitor permanently responded: Dew point monitor permanently responded - cooling function is blocked. | Partly | Yes |
| 060 | Heat source temperature: The measured heat source outlet temperature is below the minimum heat source temperature. | Yes | Yes |
| 061 | Heat source temperature approaching critical value: Heat source outlet temperature reaches a critical value (min. heat source temperature + 2 K). | No | Yes |
| 062 | Winding protection: The compressor winding protection has tripped (< 3 times in 24 h). | Yes | Yes |
| 063 | Winding protection - lockout: The compressor winding protection has tripped (> 3 times in 24 h). The heat pump is no longer operated. | Yes | Yes |
| 067 | Heat source temperature - lockout: The minimum heat source outlet temperature was undershot (> 5 times in 24 h). The heat pump is no longer operated. | Yes | Yes |
| 070 | EIB/KNX module fault: No EIB-KNX module is connected to the Navigator main board or the module is not programmed (shown 30 s after parameterisation). | No | Yes |
| 074 | Soft starter 2 (see LED): Soft-starter fault on the second compressor; type of fault shown on the soft starter. | Partly | Yes |
| 075 | Soft starter 2 - lockout: Soft-starter fault on the second compressor (> 5 times in 24 h). The heat pump is no longer operated. | Yes | Yes |
| 080 | Summary fault stage 1: Compressor 1 is switched off - check soft starter. | Partly | Yes |
| 081 | Summary fault stage 1 - lockout: Compressor 1 is no longer operated. | Partly | Yes |
| 082 | Summary fault stage 2: Compressor 2 is switched off - check soft starter. | Partly | Yes |
| 083 | Summary fault stage 2 - lockout: Compressor 2 is no longer operated. | Partly | Yes |
| 084 | Summary fault stage 3: Compressor 3 is switched off - check soft starter. | Partly | Yes |
| 085 | Summary fault stage 3 - lockout: Compressor 3 is no longer operated. | Partly | Yes |
| 086 | Summary fault stage 4: Compressor 4 is switched off - check soft starter. | Partly | Yes |
| 087 | Summary fault stage 4 - lockout: Compressor 4 is no longer operated. | Partly | Yes |
| 088 | Expansion valve 1: Expansion valve driver, refrigerant circuit 1. | Not stated | Yes |
| 089 | Expansion valve 2: Expansion valve driver, refrigerant circuit 2. | Not stated | Yes |
| 090 | Central unit 1 not online: Communication problem - master board A1 not found. | Not stated | Yes |
| 091 | Central unit 2 not online: Communication problem - slave board A7 not found. | Not stated | Yes |
| 095 | Operating limit exceeded: Operation outside (above) the compressor envelope: at the current evaporating temperature the condensing temperature is outside the operating range. | Not stated | Yes |
| 096 | Operating limit MOP: Operation outside the compressor envelope: at the current condensing temperature the evaporating temperature is outside the operating range. | Not stated | Yes |
| 100 | Sensor fault: Outdoor sensor (B32) - short circuit. | Not stated | Yes |
| 101 | Sensor fault: Outdoor sensor (B32) - open circuit (break). | Not stated | Yes |
| 102 | Sensor fault: Heat pump flow sensor (B33) - short circuit. | Not stated | Yes |
| 103 | Sensor fault: Heat pump flow sensor (B33) - open circuit (break). | Not stated | Yes |
| 104 | Sensor fault: HGL flow sensor (B35) - short circuit. | Not stated | Yes |
| 105 | Sensor fault: HGL flow sensor (B35) - open circuit (break). | Not stated | Yes |
| 106 | Sensor fault: Heat source outlet sensor (B36) - short circuit. | Not stated | Yes |
| 107 | Sensor fault: Heat source outlet sensor (B36) - open circuit (break). | Not stated | Yes |
| 108 | Sensor fault: Heat storage/buffer tank sensor (B38) - short circuit. | Not stated | Yes |
| 109 | Sensor fault: Heat storage/buffer tank sensor (B38) - open circuit (break). | Not stated | Yes |
| 110 | Sensor fault: Cold storage tank sensor (B40) - short circuit. | Not stated | Yes |
| 111 | Sensor fault: Cold storage tank sensor (B40) - open circuit (break). | Not stated | Yes |
| 112 | Sensor fault: DHW cylinder sensor bottom (B41) - short circuit. | Not stated | Yes |
| 113 | Sensor fault: DHW cylinder sensor bottom (B41) - open circuit (break). | Not stated | Yes |
| 114 | Sensor fault: Fresh water station sensor (B42) - short circuit. | Not stated | Yes |
| 115 | Sensor fault: Fresh water station sensor (B42) - open circuit (break). | Not stated | Yes |
| 116 | Sensor fault: Flow sensor heating circuit A (B51) - short circuit. | Not stated | Yes |
| 117 | Sensor fault: Flow sensor heating circuit A (B51) - open circuit (break). | Not stated | Yes |
| 118 | Sensor fault: Flow sensor heating circuit B (B52) - short circuit. | Not stated | Yes |
| 119 | Sensor fault: Flow sensor heating circuit B (B52) - open circuit (break). | Not stated | Yes |
| 120 | Sensor fault: Room sensor heating circuit A (B61) - short circuit. | Not stated | Yes |
| 121 | Sensor fault: Room sensor heating circuit A (B61) - open circuit (break). | Not stated | Yes |
| 122 | Sensor fault: Room sensor heating circuit B (B62) - short circuit. | Not stated | Yes |
| 123 | Sensor fault: Room sensor heating circuit B (B62) - open circuit (break). | Not stated | Yes |
| 124 | Sensor fault: Hot gas sensor (B71) - short circuit. | Not stated | Yes |
| 125 | Sensor fault: Hot gas sensor (B71) - open circuit (break). | Not stated | Yes |
| 126 | Sensor fault: Room humidity sensor (B31) - short circuit. | Not stated | Yes |
| 127 | Sensor fault: Room humidity sensor (B31) - open circuit (break). | Not stated | Yes |
| 128 | Sensor fault: Low pressure sensor - short circuit. | Not stated | Yes |
| 129 | Sensor fault: Low pressure sensor - open circuit (break). | Not stated | Yes |
| 130 | Sensor fault: Flow sensor heating circuit C (B53) - short circuit. | Not stated | Yes |
| 131 | Sensor fault: Flow sensor heating circuit C (B53) - open circuit (break). | Not stated | Yes |
| 132 | Sensor fault: Flow sensor heating circuit D (B54) - short circuit. | Not stated | Yes |
| 133 | Sensor fault: Flow sensor heating circuit D (B54) - open circuit (break). | Not stated | Yes |
| 134 | Sensor fault: Room sensor heating circuit C (B63) - short circuit. | Not stated | Yes |
| 135 | Sensor fault: Room sensor heating circuit C (B63) - open circuit (break). | Not stated | Yes |
| 136 | Sensor fault: Room sensor heating circuit D (B64) - short circuit. | Not stated | Yes |
| 137 | Sensor fault: Room sensor heating circuit D (B64) - open circuit (break). | Not stated | Yes |
| 138 | Sensor fault: Flow sensor heating circuit E (B55) - short circuit. | Not stated | Yes |
| 139 | Sensor fault: Flow sensor heating circuit E (B55) - open circuit (break). | Not stated | Yes |
| 140 | Sensor fault: Flow sensor heating circuit F (B56) - short circuit. | Not stated | Yes |
| 141 | Sensor fault: Flow sensor heating circuit F (B56) - open circuit (break). | Not stated | Yes |
| 142 | Sensor fault: Flow sensor heating circuit G (B57) - short circuit. | Not stated | Yes |
| 143 | Sensor fault: Flow sensor heating circuit G (B57) - open circuit (break). | Not stated | Yes |
| 144 | Sensor fault: Room sensor heating circuit E (B65) - short circuit. | Not stated | Yes |
| 145 | Sensor fault: Room sensor heating circuit E (B65) - open circuit (break). | Not stated | Yes |
| 146 | Sensor fault: Room sensor heating circuit F (B66) - short circuit. | Not stated | Yes |
| 147 | Sensor fault: Room sensor heating circuit F (B66) - open circuit (break). | Not stated | Yes |
| 148 | Sensor fault: Room sensor heating circuit G (B67) - short circuit. | Not stated | Yes |
| 149 | Sensor fault: Room sensor heating circuit G (B67) - open circuit (break). | Not stated | Yes |
| 150 | Sensor fault: Suction gas sensor evaporator outlet (B79) - short circuit. | Not stated | Yes |
| 151 | Sensor fault: Suction gas sensor evaporator outlet (B79) - open circuit (break). | Not stated | Yes |
| 152 | Sensor fault: Low pressure transmitter (B78) - short circuit. | Not stated | Yes |
| 153 | Sensor fault: Low pressure transmitter (B78) - open circuit (break). | Not stated | Yes |
| 154 | Sensor fault: Solar collector sensor (B73) - short circuit. | Not stated | Yes |
| 155 | Sensor fault: Solar collector sensor (B73) - open circuit (break). | Not stated | Yes |
| 156 | Sensor fault: Solar charging sensor (B74) - short circuit. | Not stated | Yes |
| 157 | Sensor fault: Solar charging sensor (B74) - open circuit (break). | Not stated | Yes |
| 158 | Sensor fault: Solar collector return sensor (B75) - short circuit. | Not stated | Yes |
| 159 | Sensor fault: Solar collector return sensor (B75) - open circuit (break). | Not stated | Yes |
| 160 | Sensor fault: Solar heat source reference sensor (B76) - short circuit. | Not stated | Yes |
| 161 | Sensor fault: Solar heat source reference sensor (B76) - open circuit (break). | Not stated | Yes |
| 162 | Sensor fault: Intake air sensor (B37) - short circuit. | Not stated | Yes |
| 163 | Sensor fault: Intake air sensor (B37) - open circuit (break). | Not stated | Yes |
| 164 | Sensor fault: Air heat exchanger sensor (B72) - short circuit. | Not stated | Yes |
| 165 | Sensor fault: Air heat exchanger sensor (B72) - open circuit (break). | Not stated | Yes |
| 166 | Sensor fault: High pressure transmitter (B86) - short circuit. | Not stated | Yes |
| 167 | Sensor fault: High pressure transmitter (B86) - open circuit (break). | Not stated | Yes |
| 168 | Sensor fault: Liquid line sensor (B87) - short circuit. | Not stated | Yes |
| 169 | Sensor fault: Liquid line sensor (B87) - open circuit (break). | Not stated | Yes |
| 170 | Sensor fault: Heat pump return sensor (B34) - short circuit. | Not stated | Yes |
| 171 | Sensor fault: Heat pump return sensor (B34) - open circuit (break). | Not stated | Yes |
| 172 | Sensor fault: Heat source inlet sensor (B43) - short circuit. | Not stated | Yes |
| 173 | Sensor fault: Heat source inlet sensor (B43) - open circuit (break). | Not stated | Yes |
| 178 | Sensor fault: Charging sensor (B45) - short circuit. | Not stated | Yes |
| 179 | Sensor fault: Charging sensor (B45) - open circuit (break). | Not stated | Yes |
| 196 | Sensor fault: DHW cylinder sensor top (B48) - short circuit. | Not stated | Yes |
| 197 | Sensor fault: DHW cylinder sensor top (B48) - open circuit (break). | Not stated | Yes |
| 200 | Operating limit reached: Operation outside the operating range on air-source heat pumps. | Not stated | Yes |
| 221 | Low pressure fault 2 (second refrigerant circuit): The low pressure switch has switched the heat pump off (< 3 times in 24 h). | Yes | Yes |
| 231 | Low pressure fault 2 - lockout (second refrigerant circuit): The low pressure switch has switched the heat pump off (> 3 times in 24 h). The heat pump is no longer operated. | Yes | Yes |
| 236 | Safety defrost interval 0.1-0.5 set: The safety defrost interval is set to 0.1-0.5 h. | No | Yes |
| 237 | Charging pump fault in bivalent operation: Fault contact of the charging pump tripped during operation of the bivalent (second) heat generator. | Partly | Yes |
| 241 | High pressure fault 2 (second refrigerant circuit): The high pressure switch has switched the heat pump off. | Yes | Yes |
| 244 | Flow monitoring heating side in bivalent operation: Works like fault 44 but acts on the bivalent generator when the charging pump is configured "YES"; heating-side flow monitor responded. | Partly | Yes |
| 251 | High pressure fault 2 - lockout (second refrigerant circuit): The high pressure switch has switched the heat pump off (> 3 times in 24 h). The heat pump is no longer operated. | Yes | Yes |
| 270 | Stages blocked long-term: Triggered when all compressor stages have been blocked for more than 10 hours; leads to a summary fault so the bivalent generator is available above the bivalence point. | Yes | Yes |
| 271 | Bivalent generator manually activated: Information that the bivalent (backup) generator was manually activated - reminder to switch it off to avoid high running costs. | No | Yes |
| 272 | Bivalent operation with reduced temperature: Bivalent generator active due to a summary fault: temperature levels reduced (ECO) and no DHW production until "Bivalent only" operating mode is selected. Warning: increased heating costs. | Partly | Yes |
| 280 | Collector maximum temperature: Solar collector maximum temperature exceeded; resets automatically when it falls below. | No | Yes |
| 281 | DHW cylinder maximum temperature: DHW cylinder maximum temperature exceeded; resets automatically. | Partly | Yes |
| 282 | Heat storage maximum temperature: Maximum buffer temperature exceeded; resets automatically. | Partly | Yes |
| 283 | Heat source maximum temperature: Maximum heat source temperature exceeded; resets automatically. | Partly | Yes |
| 284 | Solar module not present: Solar control configured but no CAN-bus communication with the solar module. | No | Yes |
| 301 | Boost function - temperature not reached: Boost temperature not reached or DHW cylinder temperature higher than 85°C. | No | Yes |
| 302 | Legionella function - temperature not reached: Legionella temperature not reached or DHW cylinder temperature higher than 85°C. | No | Yes |
| 500 | Outdoor unit intake sensor defective: Intake (air) sensor in the outdoor unit defective. | Not stated | Yes |
| 501 | Outdoor unit suction gas sensor defective: Suction gas sensor in the outdoor unit defective. | Not stated | Yes |
| 502 | Outdoor unit hot gas sensor defective: Hot gas sensor in the outdoor unit defective. | Not stated | Yes |
| 503 | Outdoor unit low pressure sensor defective: Low pressure sensor in the outdoor unit defective. | Not stated | Yes |
| 504 | Outdoor unit high pressure sensor defective: High pressure sensor in the outdoor unit defective. | Not stated | Yes |
| 505 | Outdoor unit high pressure: Outdoor unit high pressure fault. | Yes | Yes |
| 506 | Outdoor unit low pressure: Outdoor unit low pressure fault. | Yes | Yes |
| 507 | Hot gas temperature: Hot gas temperature outside the operating limits. | Not stated | Yes |
| 508 | Differential pressure too low: Differential pressure between low and high pressure side too small. | Not stated | Yes |
| 509 | Outdoor unit start-up error: 5 unsuccessful start attempts. | Yes | Yes |
| 510 | Operating limit exceeded (outdoor unit): Outside the operating range for more than 5 minutes. | Not stated | Yes |
| 511 | Superheat too low: Too low or negative superheat. | Not stated | Yes |
| 512 | MOP fault: Maximum operating pressure exceeded. | Not stated | Yes |
| 513 | Suction gas temperature too low: Suction gas temperature too low. | Not stated | Yes |
| 514 | EEV control: Control problem with electronic expansion valve. | Not stated | Yes |
| 515 | Inverter communication fault: Fault between outdoor board and inverter. | Yes | Yes |
| 516 | Outdoor unit communication: Communication fault on the Modbus link between indoor unit and outdoor unit. | Yes | Yes |
| 517 | Inverter fault: The inverter has a fault. | Yes | Yes |
| 520 | Outdoor unit software: Wrong software on the outdoor unit or wrong software loaded. | Yes | Yes |
| 521 | Timeout inputs/outputs: Carel board cannot establish a bus connection. | Not stated | Yes |
| 522 | Timeout converter: Converter/inverter cannot establish a bus connection. | Not stated | Yes |
| 523 | Timeout fan: Fan cannot establish a bus connection. | Not stated | Yes |
| 524 | Outdoor unit emergency stop C1: Outdoor unit emergency stop refrigerant circuit 1. | Yes | Yes |
| 525 | Outdoor unit emergency stop C2: Outdoor unit emergency stop refrigerant circuit 2. | Yes | Yes |
| 526 | Outdoor unit emergency stop C1 - lockout: Outdoor unit emergency stop refrigerant circuit 1 - lockout. | Yes | Yes |
| 527 | Outdoor unit emergency stop C2 - lockout: Outdoor unit emergency stop refrigerant circuit 2 - lockout. | Yes | Yes |
| 530 | Inverter fault - lockout: The inverter is no longer operated (> 10 times in 24 h). The heat pump is no longer operated. | Yes | Yes |