The gas valve is taking too long to shut off, so the boiler has flagged a gas valve fault.
Most common on: ecoTEC plus, ecoTEC pro
F.62 means the boiler has detected that the gas valve is switching off too slowly — the flame is still being sensed after the valve should have closed. Because the gas valve controls the supply of gas to the burner, any delay in it shutting is treated as a fault.
It usually points to a failing gas valve or a related PCB or wiring fault. As this concerns the safe control of gas, F.62 needs a Gas Safe engineer to test and, most often, replace the gas valve.
Press reset to rule out a one-off glitch.
Because F.62 concerns the gas valve, do not clear it repeatedly if it returns — book an engineer.
A delayed gas valve shut-off needs a Gas Safe engineer to test the valve, its wiring and the PCB and replace faulty parts.
Work on the gas side of a boiler must be carried out by a Gas Safe registered engineer. The checks above are limited to safe, non-invasive things a homeowner can look at (pressure, resets, the gas supply) — if in doubt, stop and call an engineer.
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The gas valve is taking too long to shut off, so the boiler has flagged a gas valve fault. F.62 means the boiler has detected that the gas valve is switching off too slowly — the flame is still being sensed after the valve should have closed. Because the gas valve controls the supply of gas to the burner, any delay in it shutting is treated as a fault.
You can try a single reset and the safe checks below, but Vaillant F.62 usually needs a Gas Safe registered engineer. Never work on the gas side of a boiler yourself — it is illegal and dangerous unless you are Gas Safe registered.
A recurring F.62 means the underlying cause has not been fixed — most often faulty gas valve that is slow to close. Resetting repeatedly will not solve it; get the boiler diagnosed properly.