BoilerFaultCodesYour boiler's fan is running longer than necessary to clear out exhaust gases, which may temporarily stall the start-up process.
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: fan overrun
What causes this fault?
This fault occurs when the boiler's internal computer detects that the fan is spinning for too long or at an unexpected time during the ignition sequence. The most common reason is a communication error between the fan and the main control board, or the fan itself beginning to wear out and failing to stop when instructed.
DIY fix possible
Check that the outdoor flue pipe is not blocked by leaves or debrisSwitch the boiler off and back on again to reset the sequenceMonitor the boiler to see if the code clears and heating resumes naturally
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.16 — no call-out fees, no surprises.
Affiliate links — we may earn a commission at no extra cost to you.
Glow-worm Ultracom 24cx 30cx 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.