BoilerFaultCodesTechnical description
Check service mode switch is in max position
What causes this fault?
This fault occurs when the boiler is accidentally left in its manual override or 'chimney sweep' mode, which is normally used by engineers to test the system at full power. Because this mode is only meant for short-term testing, the boiler will prevent normal operation to protect the internal components from overheating. It most commonly happens when an engineer forgets to flick the internal service switch back to its normal position after a maintenance visit.
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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