BoilerFaultCodesTechnical description
Heating mode frost protection error
What causes this fault?
This fault occurs when the boiler's internal sensors detect that the water temperature has dropped near freezing levels, triggering a safety pause to prevent pipe damage. The most common reason is that the boiler is located in a very cold area, like a garage or loft, and the frost protection system has been activated to protect the heat exchanger. It can also be triggered by a faulty temperature sensor sending an incorrect freezing signal to the main control board.
This fault is almost exclusively seen during periods of extreme winter weather or prolonged cold spells when external temperatures drop below freezing.
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.