Bosch Alarm List A/W
60 fault codes documented
Alarm A21/A22/A23/A24 — No communication between system controller and remote control
The room sensor displays an error code (A21-A24) indicating no communication with the parent controller (HMC300/HPC400) via the EMS bus.
Alarm A11 — No communication via EMS BUS connection
The local device has not received its EMS token from the EMS bus master for 2 minutes, indicating a break or disruption in the EMS connection.
Alarm 1037 — Outdoor temperature sensor faulty, heating standby mode active
There is an EMS communication issue between the outdoor temperature sensor and the control unit. This can occur with alarm 1010.
Alarm 1038 — Invalid time/date
The system's time and date have not been set or were lost due to an extended power outage.
Alarm 1051 — No communication with external room temp. sensor module (Heating Circ. 1)
The system is configured to use an external room temperature sensor for heating circuit 1, but communication with the module has not been established. This may be due to an incorrect software setting.
Alarm 1052 — No communication with external room temp. sensor module (Heating Circ. 2)
The system is configured to use an external room temperature sensor for heating circuit 2, but communication with the module has not been established. This may be due to an incorrect software setting.
Warning DHW temp. sensor TW1 short circuit
The circuit for the hot water sensor TW1 is shorted, indicated by resistance below 390 Ohm.
Alarm DHW temp. sens. TW1 fault
An alarm is triggered if the hot water sensor TW1 circuit is continuously broken or shorted for 15 minutes, or if 3 warnings have occurred within 3 hours.
Alarm Z1 Electr.boost.heater E2 high li. saf. cut-out or press.reg. triggered
The electrical heater's overheating protector or the heating system's pressure guard (MC1) has been triggered. This can be due to low pressure (<0.5 bar) or overheating.
Warning Z1 Restr. in flow rate btw. outdoor and ind. unit (check strainer)
A restriction in the flow rate between the outdoor and indoor units is detected. This is indicated by a delta >13K in heating mode or >7K in cooling mode.
Warning Z1 Too high discharge gas temperature — High discharge gas temperature warning
This warning is issued if the hot gas temperature (TR6) exceeds the maximum limit (90 or 115°C) for more than 60 seconds. It relates to excessively high suction gas overheating.
Alarm Z1 Too high discharge gas temperature — Persistent high discharge gas temperature
This alarm triggers after 3 warnings (code 5310) within 3 hours, or if the high discharge gas temperature condition persists for over 30 minutes.
Warning Z1 Disch. gas temp. sensor TR6 open circuit — Discharge gas sensor open circuit
This warning indicates an open circuit (resistance over 364 kOhm) for the discharge gas temperature sensor TR6.
Warning Z1 Disch. gas temp. sensor TR6 short circuit — Discharge gas sensor short circuit
This warning signifies a short circuit (resistance below 350 kOhm) in the discharge gas temperature sensor TR6 or its signal cable, lasting for over 1 minute.
Warning Z1 Internal compressor driver fault 1 — Over-current detected
This warning is triggered by the inverter if it detects over-current (> 42 A DC) to the compressor for more than 20 microseconds. It resets automatically after 4 minutes if the condition is resolved.
Alarm Z1 Internal compressor driver fault 1 — Compressor driver issue
This alarm occurs if 3 specific warnings (code 5394) are logged within 3 hours, or if the warning is active for 30 minutes. It indicates a problem with the compressor's internal driver.
Warning Z1 Air inlet sensor TL2 open circuit — Air sensor connection issue
This warning appears if the air inlet sensor TL2 or its signal cable is broken. It triggers after 3 errors related to this sensor within 2 hours.
Warning Z1 Air inlet sensor TL2 short circuit — Air sensor shorted
This warning indicates that the circuit for the air inlet sensor TL2 is shorted (less than 900 Ohm).
Alarm Z1 Air inlet sensor TL2 fault — Air sensor failure
This alarm is triggered if 3 warnings (codes 5408, 5409) occur within 2 hours, or if the sensor TL2 is continuously shorted or broken for 15 minutes.
Warning Z1 Condensate sensor heating mode TR3 open circuit — Condensate sensor connection issue
This warning occurs if the circuit for the condensate sensor TR3 is broken (resistance over 179 kOhm).
Warning Connection problem with the power guard — Power guard communication issue
Communication between the installer module and the power guard is missing for 30 seconds. This indicates a problem with cabling or connections.
Alarm Connection problem with the power guard — Persistent power guard communication failure
This alarm is triggered if warning 5503 occurs 3 times within 3 hours, or if the communication loss persists for 30 minutes. It indicates a continuous problem with the power guard connection.
Alarm Z1 Compressor does not start — Compressor start failure
This alarm is issued if the compressor has not started within 2 minutes after a start signal was sent. It suggests an issue with the compressor's connection, the inverter, or an internal error.
Warning Z1 Condensation temp. Outside control range — High condensation temperature
This warning is issued if the condensation temperature (JR1) exceeds the allowed range for more than 30 seconds. It typically indicates too low evaporating temperature relative to condensation temperature.
Alarm Z1 Condensation temperature too high — Condensation temperature failure
This alarm is triggered after 3 warnings (code 5512) within 3 hours, or if the warning condition lasts for 30 minutes. It signifies a problem with condensation temperature control.
Warning Z1 Evap. Pressure on JR0 too low — Low evaporator pressure detected
This warning is issued if the temperature of JR0 drops below the allowed range (below -27°C) for more than 30 seconds. It suggests a blockage or low airflow in the air heat exchanger.
Alarm Z1 Evap. Pressure on JR0 too low — Evaporator pressure failure
This alarm is triggered after 3 warnings (code 5514) within 3 hours, or if the warning persists for 30 minutes, specifically during cooling mode. It indicates a persistent issue with low evaporator pressure.
Alarm Wrong combination of indoor and outdoor units — Unit mismatch
This alarm indicates that the setting of the rotary encoder on the installer board does not match the installed heat pump or indoor unit.
Warning Z1 Internal compressor driver warning 3 — Compressor driver overload
This warning is issued if the incoming AC current to the compressor exceeds 31 A, 6 times. It automatically resets after 4 minutes if the condition is no longer met.
Alarm Z1 Internal compressor driver error 3 — Persistent compressor driver error
This alarm is triggered if warning 5523 occurs 3 times within 3 hours, or if the warning condition is active for 30 minutes. It signifies a persistent internal error in the inverter affecting the compressor driver.
Alarm Z1 Too much refrigerant in cooling circuit — Overfilled refrigerant
This alarm is activated if the temperature JR1 is more than 5°C above TC3, and the subcooling exceeds the set point for over 5 minutes during hot water production. It indicates the heat pump is overfilled with refrigerant.
Alarm Pool board communication failure — Communication loss with pool board
This alarm occurs when there is no communication between the installer module and the pool board for 90 seconds, indicating a connection or cable issue.
Alarm Z1 Air in the system — Air detected in the system
This alarm indicates that the temperature of sensor TC1 has increased too rapidly (> 0.8 K/s) under normal working conditions. It's mainly for units with an integrated 9 kW electrical heater and is blocked in software v1.09 when TC0>TC1.
Warning Compressor blocked (IPM fault) — Intelligent Power Module fault
This warning is generated by the outdoor unit with error code 21, indicating an issue with the Intelligent Power Module (IPM). The outdoor unit attempts to restart every 3 minutes, but further attempts are blocked after 10 errors within 1 hour.
Alarm code 21 — Compressor blocked (IPM fault)
The outdoor unit has detected an issue with the compressor. This alarm is triggered in the indoor unit if the outdoor unit alarm has been active for over 4 minutes.
Alarm code 22 — Inverter power consumption too high
The outdoor unit is reporting high inverter power consumption, exceeding 14 A. The system may attempt to restart automatically when conditions improve.
Alarm code 23 — DC voltage outside of permissible range
The DC link voltage in the outdoor unit is either too low or too high. The unit may attempt to restart automatically when the voltage is within the normal range.
Alarm code 26 — Evaporator phase sequence incorrectly connected
There is an issue with the supply cabling to the compressor, indicated by an incorrect phase sequence. The system attempts to restart every 3 minutes, but repeated errors will block further attempts.
Alarm code 27 — Current on IGBT too high, check coil
A PSC fault has been detected, indicating excessively high current on the IGBT. The outdoor unit will attempt to restart every 3 minutes; repeated errors will block restarts.
Alarm code 29 — Evaporator power consumption too high
The evaporator is consuming too much power, triggering LG error code 29.
Alarm code 32 — Gaseous refrigerant temperature too high
The temperature of the gaseous refrigerant has become excessively high, triggering LG error code 32.
Alarm code 41 — Gaseous refrigerant sensor TH6 failure
The gaseous refrigerant sensor (TH6) has failed, triggering LG error code 41.
Alarm code 44 — Air temperature sensor of outdoor unit TL2 failure
The air temperature sensor (TL2) in the outdoor unit has failed, triggering LG error code 44.
Alarm code 45 — Average evaporator temperature sensor TR8 failure
The average evaporator temperature sensor (TR8) has failed, triggering LG error code 45.
Alarm code 46 — Suction gas temperature sensor TH5 failure
The suction gas temperature sensor (TH5) has failed, triggering LG error code 46.
Alarm code 52 — Communication error between internal HP PCBs
There is a communication error between the high-power printed circuit boards (PCBs) inside the unit, indicated by LG error code 52.
Alarm code 53 — Communication error between in- and outdoor unit
A communication error exists between the indoor and outdoor units, indicated by LG error code 53.
Alarm code 54 — Phase sequence incorrect or a phase is missing
The phase sequence is incorrect or a phase is missing, triggering LG error code 54.
Alarm code 60 — Defective EEPROM on PCB in outdoor unit
The EEPROM chip on the printed circuit board (PCB) in the outdoor unit is defective, indicated by LG error code 60.
Alarm code 61 — Temperature at condenser-pipe too high >65°C
The temperature at the condenser pipe in the outdoor unit exceeds 65°C. This alarm is triggered if the condition persists for over 15 minutes or occurs frequently.
Alarm code 62 — Temperature at heatsink too high >85°C
The temperature at the heatsink in the outdoor unit exceeds 85°C, triggering LG error code 62.
Alarm code 65 — Heatsink temperature sensor fault
There is a fault with the heatsink temperature sensor, indicated by LG error code 65.
Alarm code 73 — Compressor starting current too high
The compressor's starting current is excessively high, triggering LG error code 73.
Alarm Z1 Condensor inlet (heating) TR7 fault
There is a fault with the Z1 condenser inlet (heating) sensor TR7, indicated by an open circuit or short circuit.
Alarm Z1 Condenser inlet temperature sensor TR3 failure
The Z1 Condenser inlet temperature sensor TR3 has failed, indicated by an open circuit or short circuit.
Alarm code 43 — Z1 Pressure sensor failure
The Z1 pressure sensor has failed, indicated by an open circuit or short circuit, triggering LG error code 43.
Alarm code 48 — Z1 Liquid in cooling sensor TR4 fault
The Z1 liquid in cooling sensor TR4 has failed, triggering LG error code 48.
Alarm code 35 — Z1 Low evap. pressure
The evaporator pressure is too low, triggering LG error code 35.
Alarm code 55 — Z1 Communication error btw. indoor and outdoor unit
A communication error exists between the indoor and outdoor units, indicated by LG error code 55.
Alarm code 67 — Z1 Outdoor unit fan blocked
The fan in the outdoor unit is blocked, triggering LG error code 67.