Bosch Error Codes

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Bosch Error Codes And Troubleshooting Guide


Bosch heaters are a top choice for any household in Australia, but this does not mean that they are immune to faults or glitches. Here are the most common error codes for Bosch hot heater systems and exactly how to fix each one.


Bosch Error Codes

CODE: 11

Problem: Fault in the unit ignition.

Solution: Check the gas valve is open and the supply is sufficient. Check this by lighting the gas stove, if it doesn’t light there is a problem with the supply.

CODE: 29

Problem: Something in the units’ neutraliser is clogged.

Solution: Try resetting the controller by turning the main power off and on.

CODE: 90

Problem: Abnormal combustion or law gas supply pressure.

Solution: Turn the control unit off, turn the hot water tap on and turn the control unit on.

CODE: 92

Problem: The water heater’s neutraliser is in need of replacement.

Solution: Get in touch with a plumber to replace the neutraliser.

CODE: 99

Problem: Your hot water system has shut down due to abnormal combustion.

Solution: If turning the main power off and on again does not work, you will need to get in contact with a qualified plumber with experience in hot water systems.

CODE: A0

Problem: There is a problem with your heaters hot and cold sensors.

Solution: Turn the unit off, turn on the hot water tap and turn the power back on.


CODE: A1

Problem: The temperature within the hot water unit is hotter than average.

Solution: The only way to clear the A1 code is to call a qualified plumber.

CODE: A4

Problem: This code means that the air temperature sensor is faulty.

Solution: The only way to clear the A4 code is to call a qualified plumber.

CODE: A7

Problem: This code means that the water temperature sensor is faulty.

Solution: The only way to clear the A7 code is to call a qualified plumber.

CODE: A9

Problem: No hot water or inconsistent temperatures.

Solution: Turn the power off, turn on the hot water and turn the power back on. If this doesn’t work, check the gas supply pressure.

CODE: C1

Problem: Little to no air flow meaning that the heater cannot start up.

Solution: Turn the hot water tap on to its full capability and then turn it off. Then turn the system on and off.

CODE: C7

Problem: A faulty fan, only cold water will be able to be used.

Solution: The only way to clear the C7 code is to call a qualified plumber.

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