BoilerFaultCodesWhat the manual says
Manufacturer manualCOMMUNICATION FAULT: THIS FAULT MAY BE OCCASIONAL AND CAUSED BY ELECTROMAGNETIC INTERFERENCE, OTHERWISE CHECK THE MAIN CONTROL BOARD (PCB).
What causes this fault?
This fault occurs when the 'brain' of the boiler loses contact with its internal electrical components, meaning it can no longer send or receive instructions. It is usually caused by a loose connection in the wiring or a hardware failure within the main control board itself. Occasionally, outside electrical interference from other household appliances can disrupt these signals and trigger the error.
Engineer required
This is a high severity fault. Stop using the boiler and call a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
Avoid the next call-out bill
A cover plan would handle faults like 20: no call-out fees, no surprise bills.
Affiliate links. We may earn a commission at no extra cost to you.