BoilerFaultCodesYour boiler has reached its safety limit for monitoring the gas flame and cannot adjust itself correctly to heat your home.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: Regulation current value has been reached. Try resetting the boiler, check the gas pressure and check the combustion values and CO2 calibration – if this doesn’t work the board or valve needs replacing.
What causes this fault?
This fault occurs when the boiler's control system can no longer accurately monitor or adjust the flame to ensure safe burning. It usually means the electronic signals between the gas valve and the main control board have drifted outside of safe limits, often due to a failing component or poor gas flow. As a result, the boiler shuts down because it cannot guarantee the fuel is burning efficiently or safely.
DIY fix possible
Press and hold the reset button for 3 secondsEnsure your gas meter has credit (if applicable)Check that other gas appliances in your home are working correctly
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 E78 — no call-out fees, no surprises.
Affiliate links — we may earn a commission at no extra cost to you.
Could it be time for a new boiler?
If repair costs are adding up, a new energy-efficient boiler could be the smarter long-term choice.
Affiliate links — we may earn a commission at no extra cost to you.