BoilerFaultCodesTechnical description
Over temperature on primary water circuit
What causes this fault?
This fault occurs when the water inside the boiler gets too hot, causing a safety sensor to trip and shut the system down. The most common reasons are a pump that has stopped moving water around the system or a build-up of sludge and debris that is blocking the internal pipework.
This fault is more common when the heating is first turned back on in autumn, as static water can lead to pump seizures or settled debris causing blockages.
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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