BoilerFaultCodesTechnical description
water flow fault
What causes this fault?
This fault occurs when the boiler's internal sensors detect that water isn't moving through the unit quickly enough to safely carry heat away from the burner. The most common reasons are a failed internal pump, a build-up of debris causing a blockage in the pipework, or air trapped within the system. It can also be triggered if the system pressure has dropped too low for the pump to operate effectively.
This issue often surfaces during the first cold spell of autumn when the heating is turned on after being idle all summer, which can cause the internal pump 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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