BoilerFaultCodesTechnical description
Service Function: Max. CH flow temperature
What causes this fault?
This fault occurs when the water inside the boiler gets too hot too quickly, causing the system to shut down for safety. The most common reasons are a lack of water flow caused by a sticking pump or a sensor that has become faulty and is giving a false temperature reading. It can also happen if air is trapped in the heat exchanger or if the system is partially blocked with debris.
This fault is more common in autumn when homeowners first turn their heating back on after summer, as pump components can seize up during long 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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