Last updated on October 6th, 2024
The Vaillant boiler F29 fault code, like all Vaillant boiler fault codes, shows on the display 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.
I have been a full-time boiler repairer for over a decade and having fault codes on the screen when I arrive is very welcome. In this post, I’ll go through some of the reasons for your F29 fault and some potential fixes.
What Does an F29 Fault Mean?
Here is what the Vaillant Ecotec manual says about their F.29 fault code:
The most likely cause of an F29 fault code (the same as Glow-worm F29) is the boiler has been locked out due to a gas supply fault or a blocked condensate pipe. An F29 fault could also mean that a part on the boiler is broken and needs to be replaced, but most of the time it’s a gas supply issue.
How to Fix an F29 Fault
To fix this fault, the first thing I would do is check:
- The gas is turned on at the gas meter
- If you have a prepayment gas meter, then make sure you are in credit, as this is quite a common situation I come across
- If you have other gas appliances, like a gas hob or gas fire, then check to see if these are working to find out if you have a gas problem. If they don’t work, then you have a gas supply problem
- Check for a blocked or frozen condensate pipe
Other Causes of an F29 Fault
A gas supply problem is the most common cause of an F29 fault, but here are some other potential causes:
- Faulty gas valve: Might need a new one
- Worn-out spark electrodes: Might need to be cleaned or replaced
- Faulty PCB (printed circuit board): The PCB is the brain of the boiler and might need to be replaced
- Frozen condensate pipe: If it’s freezing outside, then having a frozen condensate pipe is possible. You can pour hot water on it to melt the frozen condensate and reset the boiler. Dealing with frozen condensate pipes on Vaillant boilers
Gas Pressure
Low gas pressure (or no gas) is a common cause of an F29 error. You need to make sure you’re getting enough gas but low gas pressure can also be caused by a faulty gas valve. You can do all the checks needed to find out if you’re getting enough gas but you might need to get a Gas Safe engineer in to replace a faulty gas valve.
You also might need to call your gas supplier if your other gas appliances aren’t working as there might be a problem with your gas meter or a gas pipe problem in the street.
Vaillant 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.
Resetting a 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 must press the button to reset the boiler. Sometimes you have to hold it down for 3 seconds, but on some Vaillant boilers, it just needs to be pressed.
Vaillant Boiler Guides
- Vaillant boiler not firing up
- Vaillant boiler no hot water
- Vaillant boiler leaking
- Vaillant boiler pressure
- Vaillant F54 fault
- Vaillant F22 fault
- Vaillant F75 fault
- Vaillant F83 fault
Summary
A Vaillant F29 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. If it’s freezing outside then you probably have a frozen condensate pipe. If it’s not any of these problems then it’s probably a gas valve or PCB problem which you’ll need to call a Gas Safe engineer to fix.
Feel free to ask any questions in the comments below, and I’ll do my best to help. If you found this post helpful, please consider sharing it.
