BoilerFaultCodesWhat the manual says
Manufacturer manualCondensate pump fault
What causes this fault?
This fault occurs when the safety system detects that the acidic water produced during the heating process cannot be drained away safely. The most common reasons are a physical blockage in the drainage pipes or a mechanical failure in the pump responsible for pushing that waste water out of the property.
This fault is significantly more common during freezing winter temperatures, as the external waste pipe can freeze solid and cause water to back up into the boiler.
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.
Avoid the next call-out bill
A cover plan would handle faults like F77: no call-out fees, no surprise bills.
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Related fault codes
All 52 fault codes on the Flexicom hx
Seeing a different code? Every code this model can display, in one place.