F.42 - Coding resistance fault (output range/gas group)

What does F.42 mean?

There is a fault with the coding resistance, which specifies the boiler's output range or gas group. This can be due to a short circuit or interruption in the resistance or its wiring.

• Short circuit or interruption in the output range coding resistance (in the cable harness at the heat exchanger).
• Short circuit or interruption in the gas group resistor (on the PCB).

Click steps to track your progress.

1. 1

   Press the reset button on the boiler display up to three times to try and clear the fault.

2. 2

   Contact the installer or customer service immediately. This fault indicates an issue with the coding resistance for either the output range or gas group.

3. 3

   A qualified technician will need to check the resistance components and associated wiring on the PCB and in the cable harness.