Vaillant boiler F54 fault code

How to Fix F54 Vaillant Boiler Fault: Repair Guide

Last updated on June 10th, 2024

The F54 Vaillant boiler fault code, and other Vaillant boiler fault codes, show on the boiler screen when there is a problem and your boiler locks out.

Vaillant uses them to show you what might be wrong with the boiler not firing up.

Having fault codes on the screen is a great way to help diagnose your boiler problems.

I have been carrying out boiler repairs for over a decade and having fault codes on the screen when I arrive is very welcome.

Not all boilers use fault codes, so having them is a huge bonus.

What Does F54 Mean on a Vaillant Boiler?

The Vaillant F54 fault code means insufficient gas supply.

This means the boiler will not work as the gas valve is not supplied with enough gas to heat the water in the boiler.

Here’s what the Vaillant Ecotec manual says about F.54 Vaillant fault:

What Does F54 Mean on a Vaillant Boiler
F.54 Vaillant fault code meaning

How to Fix F54 Fault on a Vaillant Boiler

To fix the F54 fault code on your Vaillant boiler, the first thing I would check is the ECV (emergency control valve) at the gas meter is fully open.

The ECV is fully open when the handle is in line with the gas pipe.

If the handle is across, or not fully in line with the gas pipe, then the gas may be getting restricted by the ECV, causing the boiler to lock out and show the Vaillant F54 fault code.

F54 Vaillant Boiler Fault Reset

The first thing I would do on a Vaillant boiler that is not working, no matter what fault code is showing, is to check the pressure and reset the boiler.

Knowing how to reset a Vaillant boiler is the simplest way to get your boiler working again, as it might have just locked out.

To reset a Vaillant boiler, you must find the reset button. This is usually a flame with a line through it. You have to press the button to reset the boiler.

Vaillant boiler reset button
Vaillant reset button

Sometimes you have to hold it down for 3 seconds, but on some Vaillant boilers, it just needs to be pressed.

Other Causes of an F54 Fault Code

After checking the ECV at the gas meter, here are some other possibilities that could be restricting the gas supply and causing the F54 fault code:

  • The undersized gas pipe supply from the gas meter to the boiler: The gas pipe needs to be upgraded.
  • Blocked or dented gas pipe: The gas pipe might have built up with debris inside or been accidentally damaged. The gas pipe will need to be cleaned out or replaced.
  • A partially closed isolating gas valve on the gas pipe: The full length of the gas supply will need to be checked for gas valves and make sure they’re fully open.
  • Not getting enough gas to the property: The gas will need to be tested with a manometer to see if the property is getting enough gas. If it’s not, then the gas supplier is responsible for making sure it is.
  • Faulty gas valve: The gas valve might need to be replaced.
How to read a gas meter

Vaillant Boiler Guides


A Vaillant F54 error on your boiler can be easily fixed without opening the boiler.

Make sure to verify you are getting gas by checking the gas meter ECV and that you have credit if you use a pre-payment gas meter.

Feel free to ask me any questions in the comment section below and I’ll try my best to help.

Please share this post if you find it helpful.


How do you clear the fault code on a Vaillant boiler?

To clear the fault code on a Vaillant boiler, you must reset the boiler. If the fault code appears after resetting the boiler, you must find and repair the problem causing your Vaillant boiler to lock out and show a fault code.

Why is my Vaillant boiler not turning on?

If your Vaillant boiler is not turning on at all, and nothing is on the display, then you probably have an electric supply issue.

You should check the fused spur switch that should be next to the boiler. Make sure it is switched on and the 3 amp fuse is good. It could also be that the fuse at the main board (consumer unit) has tripped, so you can there too.


  • Steven Reid

    I am a full-time plumber and Gas Safe registered engineer. I incorporated Housewarm Ltd. in 2011 to provide heating and plumbing services to homes in Newcastle upon Tyne, England. I now blog about what I've learned over the years to help DIYers and plumbers.

    View all posts
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