BoilerFaultCodesTechnical description
Variation on temperature of primary and/or return too high
What causes this fault?
This fault occurs when the internal sensors detect the water temperature within the boiler is rising too rapidly or behaving erratically. This is usually caused by a blockage or a pump failure that prevents water from flowing through the system quickly enough to carry the heat away.
This issue often surfaces in autumn or winter when the heating is first turned on after being idle, as pump components can seize during the summer months.
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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