Vaillant F62 Fault Code Explained
Hertfordshire, Bedfordshire & Cambridgeshire
An F62 fault on a Vaillant boiler relates to a delay in the gas valve shutting off at the end of a cycle.
This is a gas valve fault code. It is not a homeowner job and it should not be worked around.
What F62 actually means
At the end of a heating cycle the gas valve should close promptly and the flame should go out. The boiler monitors that. If the valve appears to shut late, or the flame signal persists longer than it should, the appliance locks out.
The boiler cannot distinguish a genuinely slow valve from a sensor giving a misleading signal, so it treats it as the more serious of the two.
What you can safely check yourself
Nothing on this one. There is no homeowner check that helps with F62, and the components involved are inside the appliance. This needs a Gas Safe engineer.
When to stop, and why
What causes it beyond the simple checks
A failing gas valve, a flame sensing electrode giving a delayed or false signal, or a PCB fault. Diagnosis needs test equipment and Gas Safe qualification.
How Vantage can help
We are Gas Safe registered and cover Hertfordshire, Bedfordshire and Cambridgeshire, with an emergency line answered 24 hours a day.
Call us on 01462 506374. See also boiler repair and Vaillant boiler installation.
Frequently asked questions
Can I keep using the boiler?
No. Turn it off and have it looked at.
Is this dangerous?
The lockout is the safety system working. The underlying fault needs diagnosing rather than clearing.
Is it always the gas valve?
Not always. It can be the sensor or the board, which is why it needs testing rather than guessing.
Related fault codes
Other Vaillant codes: Vaillant F22 · Vaillant F75 · Vaillant F28 · Vaillant F29 · Vaillant F27 · Vaillant F20 · Vaillant F23 · Vaillant F83 · Vaillant F32 · Vaillant F61 · Vaillant F72
See also our guide to boiler not firing up, the full boiler advice section, and boiler repair.
In Vaillant’s own words
Vaillant describes F62 as the flame switch-off being detected after a delay.
The gas valve should close cleanly at the end of a cycle. When it does not, the boiler locks out rather than allow gas past a valve it cannot trust. That is a component fault, not a settings problem, and it should not be worked around.
When to call an engineer
Anything past the free checks above needs a Gas Safe engineer with the right test kit. Ring Vantage on 01462 506374, any hour, any day of the year. You will get an honest arrival time rather than a comforting one, and the price before the work.
Need help today?
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Vantage Plumbing and Heating covers Hertfordshire, Bedfordshire and the surrounding areas. Call and talk to an engineer, or send us the details and we will come back to you with a price.
Gas Safe registered, number 956889. Emergency line answered 24/7.