BoilerFaultCodesTechnical description
Boiler in very cold environment (less than 5°C) or damp control board.
What causes this fault?
This fault occurs when the boiler's internal sensors detect that the air temperature inside the casing has dropped below 5°C, posing a risk of freezing. It can also be triggered if high levels of moisture or dampness have reached the control board, causing the electronics to misread the temperature. The system shuts down as a safety precaution to prevent structural damage from ice or electrical short circuits.
This fault is almost exclusively seen during extreme winter cold spells or if the boiler is located in an unheated outbuilding or garage.
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.