BoilerFaultCodesWhat the manual says
Manufacturer manualPump does not run when domestic hot water demand is active
Shared across the range
This code is shared by the boilers in this range, which use the same control board. It may not be printed in this exact variant’s manual.
What causes this fault?
This fault occurs when the boiler detects that water isn't moving through the internal tank even though you have turned on a hot tap. The most common reason is a seized or failing internal pump, but it can also be caused by a faulty flow sensor that fails to tell the boiler to start the heating process.
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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Related fault codes
All 57 fault codes on the Highflow 300
Seeing a different code? Every code this model can display, in one place.