BoilerFaultCodesTechnical description
No flow (flow/return dt > 45K)
What causes this fault?
This fault occurs when the boiler detects that water is heating up far too quickly because it isn't circulating through the pipes as it should. The most common reasons are a failed pump that can no longer push water around or a significant blockage within the internal pipework that is restricting flow.
This issue is frequently seen at the start of autumn when heating systems are turned back on after sitting idle all summer, which can cause internal pump parts to seize.
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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