BoilerFaultCodesTechnical description
The actual temperature recorded by the flow temperature sensor or return temperature sensor is rising too quickly
What causes this fault?
This fault occurs when the heat exchanger gets too hot too quickly because water isn't moving away from it fast enough. The most common reasons are a failing circulation pump, a blockage in the pipework, or air trapped within the system preventing the flow of water.
This issue often surfaces in autumn when the heating is turned back on after a long summer break, as internal pump components can seize during periods of inactivity.
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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