BoilerFaultCodesTechnical description
Insufficient system flow (if the system flow is too low for a certain length of time boiler will switch off)
What causes this fault?
This fault occurs when the water inside the boiler heats up too quickly because it is not being pumped away through your radiators effectively. The most common reasons are a failed internal pump, a build-up of sludge blocking the pipework, or air trapped within the heating system preventing smooth circulation.
This issue often comes to light during the autumn when the heating is turned back on for the first time after summer, as pump components can seize 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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