BoilerFaultCodesTechnical description
Return temperature too high flow sensor temperature).
What causes this fault?
This fault occurs when the water traveling back into the boiler is nearly as hot as the water leaving it, usually because the heat isn't being released into your rooms. The most common reasons are a pump failure that isn't moving the water fast enough, or a blockage in the system like trapped air or sludgy radiators that prevents proper circulation.
This fault is more common in autumn when heating systems are switched back on after a long summer break, as pumps often 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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