Your boiler is operating normally and is currently heating either your radiators or your hot water tank.
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: CH or DHW being supplied
What causes this fault?
This is not a fault, but rather a status indicator showing that your boiler is working exactly as it should. It signifies that the internal burner is lit because there is an active demand for heat from your thermostat or hot water programmer.
You will see this code more frequently during the autumn and winter months when your central heating is scheduled to run more often.
DIY fix possible
This fault may be fixable without an engineer. Check your manual first.
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.
Ideal Mexico HE is discontinued — time for a new one?
Parts for discontinued models can be hard to find and expensive. A new A-rated boiler could save you money on both repairs and energy bills.
Affiliate links — we may earn a commission at no extra cost to you.