BoilerFaultCodesWhat the manual says
Manufacturer manual1 Check if condensate pipe blocked/frozen 2 Check if flue blocked 3 If fault persists, contact installer
What causes this fault?
This fault occurs when the boiler detects that it cannot safely expel exhaust gases through the flue or drain away waste water through the condensate pipe. The most common reasons are an external blockage in the pipes, such as debris or ice, which triggers a safety sensor to shut the system down to prevent damage or dangerous fumes.
This fault is significantly more common during freezing winter temperatures, as the external condensate pipe can freeze and prevent water from leaving 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 Blocked Flue/Condensate: no call-out fees, no surprise bills.
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