BoilerFaultCodesYour boiler is working normally and is currently providing heat to your radiators.
This is a minor fault. Keep an eye on it and mention it at your next annual boiler service. Reset the boiler and see if it clears.
Technical description: Boiler is active for central heating.
What causes this fault?
The 'C' display is not actually a fault code, but an indication that your boiler is physically firing to heat your home. It appears when the internal thermostat or external programmer calls for heat, prompting the burner to ignite and circulate hot water to your radiators. You will see this whenever your central heating is active and functioning exactly as intended.
This status code is most frequently seen during autumn and winter when the heating is scheduled to run more often.
DIY fix possible
No action is required as this is an operational status code rather than a fault.If you want the heating to turn off, lower the temperature on your room thermostat.
Find a Gas Safe engineer
Search the official register for a qualified engineer in your area.
Gas Safe Register →Protect yourself from future repair bills
A boiler cover plan would cover faults like C — no call-out fees, no surprises.
Affiliate links — we may earn a commission at no extra cost to you.