BoilerFaultCodesYour boiler is failing to light the gas or keep the flame burning, leading to a safety lockout.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: No ionisation or ionisation failure more than 5 times during one heat demand.
What causes this fault?
This fault occurs when the boiler tries to light the gas but the internal sensors cannot detect a steady flame. The most common reason is a worn-out or dirty ionisation probe that can no longer 'see' the fire, though it can also be caused by a lack of gas reaching the burner or a faulty ignition lead.
This fault can appear more frequently during the first cold snap of autumn when old electrodes that have sat idle all summer finally fail under the strain of constant use.
DIY fix possible
Check if other gas appliances in your home, like a hob, are receiving gasEnsure your gas meter has credit if you are on a pre-payment meterCheck that the gas supply valve to the boiler is fully openPress and hold the 'Reset' button for two seconds
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 e5 — no call-out fees, no surprises.
Affiliate links — we may earn a commission at no extra cost to you.
Remeha Avanta Plus 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.