Vaillant F62 boiler fault: causes and fixes

Company type: Manufacturer

HQ: Remscheid, Germany

Founded: 1874

CEO: Norbert Schiedeck

The Vaillant F62 fault code will appear when your boiler’s gas valve is not functioning properly and will likely appear after your boiler stops working. Although it is not a fatal error, it requires thorough investigation by a Gas Safe engineer.

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As the Vaillant F62 fault code signals a gas-related problem, it is a good idea to turn off your gas supply until an engineer arrives to fix it. Do not attempt any maintenance yourself, as it can be hazardous

What does the Vaillant F62 fault code mean?

In the user manual, Vaillant defines the F62 as:

Code Meaning Cause
F62 Gas valve shut off delay Gas valve leaking, electronics defective

Similar to the F28 Fault Code that we covered here, Vaillant F62 signals an issue with gas supply. The F62 signals that the gas valve is not opening and shutting correctly. In most cases, the code will show up when the boiler has detected a flow of gas when the boiler should be off, in other words, the gas valve hasn’t closed. Two key things can cause this:

  • The Gas valve is stuck in the wrong position
  • PCB is either broken or is poorly connected to some of the other boiler components

What causes the Vaillant F62?

Faulty gas valve

The gas valve is the component in the boiler that regulates the flow of gas to the burner. The gas valve will open and allow gas into the main burner when the boiler receives a signal from the PCB that heat is required (for example, when you open the tap).

Once there is enough heat, the gas valve will shut and the gas flow will stop. However, if the gas valve isn’t working properly, it may fail to shut, which will cause the sensors to detect gas flow after the instruction to shut it off, resulting in the F62 error code being shown. It's possible that the gas valve is left open, partially open, or opens at inopportune moments; any of these scenarios could be hazardous.

Faulty PCB

Usually, the root of the Vaillant F62 fault lies in the gas valve. If, however, a gas safe engineer inspects the gas valve and finds it to be in good operating order, there could be a problem with the PCB. The PCB (printed circuit board) is the brain of your boiler, as it is electronically connected to all of the boiler’s internal components and ensures they coordinate properly. The PCB controls when the gas valve opens and closes. If one of the wires is connected incorrectly or there is a break in the wiring, a problem will occur. As a result, the signal to close the gas valve may be lost, resulting in Vaillant F62.

Which boilers are more likely to display this fault?

The majority of F62 fault error codes are found on the earlier Vaillant Ecotec pro and plus R1 boilers, manufactured between 2005 and 2012. This F62 issue on these older models (at least 10 years old), is much more prevalent than on the more recent ecoTECs, which have been produced since 2012. Therefore, if you have an older boiler and see this fault code from time to time, it might be a good idea to invest into a new Vaillant boiler. Check out our review of the Vaillant combi boiler range here.

How to fix the Vaillant F62?

There is not much you can do to resolve the F62 yourself. Although resetting the boiler may return hot water for a short while, the F62 fault will keep coming back. So if you see a Vaillant F62 fault code, the right thing to do is to call a Gas Safe engineer right away.

Often the problem can be resolved by simply freeing the stuck gas valve or replacing it if it was damaged. However, if the root of the problem lies in the faulty PCB, you might require that it be replaced as well. If faulty electronics are the cause of the problem then the engineer will also check for leaks within your boiler, as this is often the cause.

A Gas Safe engineer will be able to test each component in order to pinpoint the source of the Vaillant F62 failure code.

How much will it cost to resolve the F62?

Although the Vaillant F62 fault code does not necessarily mean that your boiler can’t be repaired and you need to replace it right away, it's worth assessing the repair costs first. A new gas valve can cost up to £300, and replacing a PCB is significantly more expensive – costing over £550 for the part alone. If the PCB is faulty and your boiler is more than a few years old, it is almost certainly more economical to replace the boiler rather than the PCB.

How to prevent the F62 in the future?

It is always a good idea to get your boiler serviced regularly, even after its guarantee expires. Gas Safe engineers will be able to inspect your boiler and spot any damages early on, saving you on the costly replacement parts and long repair hours.

Give your boiler a service.

Make sure you don't invalidate your warranty. Call Smart Plan to get a boiler checkup to see if everything is in good working order.

OR 020 8146 3960

Still need help with your Vaillant boiler?

Call Smart Plan and speak to our expert engineering team free of charge.

0333 772 6247