BoilerFaultCodesTechnical description
Whilst filling is in progress (constant temperature control unit)
What causes this fault?
This fault occurs when the boiler’s automated filling system becomes stuck or fails to complete its cycle, often because the system cannot reach the required pressure. The most common reason is a manual filling valve being left open by mistake or a malfunction in the electronic sensor that monitors the water level. In some cases, the internal control board may be unable to register that the filling process has finished, causing the boiler to halt for safety.
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.
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