Smell gas? Leave the property and call the National Gas Emergency line on 0800 111 999
BoilerCodes
F.62Vaillant

Vaillant F.62: the flame went out later than expected after switch-off

Checked against Vaillant's own documentation: Vaillant: boiler fault codes list and 2 more sources. Last reviewed October 2026. How we check

Engineer only

When the boiler turned the burner off, the flame took too long to go out. Vaillant lists a leaking gas valve or faulty electronics.

What you can safely do

There is nothing you can safely do yourself with this one. Leave the boiler off and book an engineer.

Before you book an engineer

  • Write down the code exactly as the display shows it: F.62.
  • Find your boiler's model name. It is usually on the front panel or in the user manual. The table below shows why it matters: Vaillant codes can mean different things on different models.
  • Note when it started and what the boiler was doing (heating, hot water, or starting up).
  • If the boiler is still under warranty, check your warranty paperwork before you book anyone.

Call a Gas Safe engineer if

  • Book a Gas Safe registered engineer.
Find a Gas Safe engineer near you Opens the official Gas Safe Register search.

Applies to ecoTEC plus. Codes can differ between models, so check your manual.

What F.62 means on each Vaillant model

From Vaillant's own fault tables. Your model name is usually on the front of the boiler or in the user manual.

ModelMeaningCauses listed for engineers
ecoTEC plusGas valve switch-off delay faultDelayed shutdown of gas valve, delayed extinguishing of flame signal, gas valve leaking, electronics defective

Common questions about Vaillant F.62

Can I keep using the boiler with F.62?

Leave it off. A delayed flame switch-off points to the gas valve and needs an engineer.

Nearby Vaillant codes

See all 36 Vaillant codes

Sources

Last reviewed October 2026. Spotted something that doesn't match your manual? Email hello@boilercodes.co.uk and we'll check it. How we check