BoilerFaultCodesYour boiler is struggling to light its flame, meaning your heating and hot water will likely stop working soon.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: Heating mode error – ignition problem
What causes this fault?
This fault occurs when the boiler's control system attempts to start the heating cycle but fails to successfully establish or detect a flame. The most common reasons include a worn-out ignition spark, a faulty gas valve not releasing fuel, or the internal sensors becoming too dirty to 'see' the flame once it has lit.
This issue is more frequent during the first cold snap of autumn when internal components that have sat idle all summer are suddenly forced to operate under high demand.
DIY fix possible
Check that your gas pre-payment meter (if you have one) has creditEnsure your gas stopcock is fully openPress the Reset button (backwards arrow or 'Flame' icon) for five 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 S.3 — no call-out fees, no surprises.
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Vaillant ecoTEC 65kW 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.
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