Last updated on January 1st, 2025
The F28 Glow-worm boiler fault code, and all Glow-worm boiler fault codes, show on the screen on the boiler when there is a problem and your boiler locks out. Glow-worm 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.
What does an F28 fault mean?
Here is what the Glow-worm Compact manual (PDF) says about their F.28 Glow-worm fault code:
The most likely cause of an F28 fault code on a Glow-worm boiler is the boiler has been locked out due to a gas supply fault. An F28 Glow-worm fault code could also mean that a part on the boiler is broken and needs to be replaced, but most of the time in my experience it is a gas supply issue. Having no gas can be checked easily without opening up the boiler.
How to fix an F28 fault
To fix the F28 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 supply problem. If they don’t work, then you might have to contact your gas supplier.
Other causes
A gas supply problem is the most common cause of a Glow-worm boiler f28 fault code, but here are some other potential causes:
- Faulty gas valve – Might need a new one.
- Worn-out spark electrodes – Might need to be 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, it is possible to have a frozen condensate pipe. You can pour hot water on it to melt the frost and reset the boiler.
Glow-worm boiler reset
The first thing I would do on a boiler that is not working, no matter what fault code is showing, is to check the pressure and reset the boiler. Resetting it is the simplest way to get your boiler working again, as it might have just locked out. To reset a Glow-worm 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. Sometimes you have to hold it down for 3 seconds, but on some Glow-worm boilers, it just needs to be pressed. If your F28 error won’t reset, you have a problem that needs to be fixed before it will reset.
Glow-worm boiler guides
- Glow-worm boiler not firing up
- Glow-worm boiler no hot water
- Glow-worm boiler pressure
- Glow-worm F83 fault
- Glow-worm F75 fault
- Glow-worm F22 fault
- Glow-worm F29 fault
Summary
A Glow-worm F28 error on your boiler can sometimes 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 any questions in the comments below, and I’ll do my best to help. If you found this post helpful, please consider sharing it.
I have a lodge in the Highlands.. at his winter I decided to leave the heating on, the boiler is set at 55, and comes on for 15 minutes every hour. I am a 3 hour drive from my lodge so the farmer is keeping an eye. Today I got a f28 on the boiler and thought I had ran out of gas (gas bottles). Turns out the bottles were not empty. The farmer done a reset and the boiler did come back on. Do I have anything to worry about? As could there be an issue causing the f28 error code.
I wouldn’t worry about it if it’s working now. The fault code would still be there and boiler locked out if was a serious problem. Sometimes they just randomly happen and clear up. If it keeps happening get it looked at.