BoilerFaultCodesTechnical description
Flow/return valves closed; Stuck pump. Appears if the boiler has overheated.
What causes this fault?
This fault occurs when water cannot travel through the boiler’s internal pipework fast enough to carry away the heat, leading to a build-up of extreme temperature. The most common reasons are a pump that has seized up or internal blockages that are preventing the water from flowing freely through the system.
This issue is frequently seen at the start of autumn when heating systems are switched back on after being idle all summer, which can cause the pump to stick.
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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