BoilerFaultCodesWhat the manual says
Manufacturer manualThe burner is supplied with too little gas or air is present in the gas pipe; check the pre-pressure. If the control pipe is not blocked, the gas/air ∆P should be checked at minimum and maximum load.
What causes this fault?
This fault occurs when the boiler's burner fails to receive the correct amount of gas required to create or maintain a stable flame. It is usually caused by air being trapped within the internal pipework after maintenance, or a failing gas valve that can no longer regulate the fuel flow correctly. Because the boiler cannot guarantee a safe and consistent burn, it will shut down to prevent damage or unsafe operation.
This issue can occasionally appear during the first cold snap of autumn when a boiler that has been idle all summer is suddenly forced to operate at maximum gas demand.
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 28: no call-out fees, no surprise bills.
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