A fault code is the boiler telling you which safety check failed. Codes differ between manufacturers, but they fall into a small number of families and the right response is usually the same.
The common code families
- Low water pressure - the system has lost water and the boiler will not run
- Ignition lockout - the boiler tried to light and could not prove a flame
- Overheat or thermistor faults - poor circulation, sludge or a failed sensor
- Fan or air pressure switch faults - the boiler cannot prove a safe flue
- Frozen condensate - very common in Newcastle during a cold snap
- PCB or communication faults - an internal electronics problem
Where to find your code
Most modern boilers show the code on the digital display. Older units may use a pattern of flashing lights instead. Note the exact code and how often it returns before calling - it saves diagnostic time.
Should you reset the boiler?
Resetting once is reasonable. If the same code returns, the fault is real and resetting simply clears the warning rather than fixing anything. Repeated lockouts on ignition or overheat faults should always be investigated.
Never remove the boiler casing to investigate a code yourself. Work inside a gas appliance is illegal unless you are Gas Safe registered.
When to call us
Tell us the make, model and code when you call and we will arrive prepared. Our vans carry the common spares, so most coded faults are resolved on the first visit.
Written by the engineering team at Newcastle Boiler Maintenance Ltd, Gas Safe registered heating engineers in Newcastle upon Tyne.