Glow-worm boilers fault codes
Glow-worm is part of the Vaillant group, and it shows in the codes: the F numbering follows the same logic as the ecoTEC range, so F22 and F75 mean substantially the same things on both. Where they differ is the display format — Glow-worm generally omits the full stop, showing F22 rather than F.22 — and the reset procedure on the Energy and Betacom ranges.
Where the code shows on a Glow-worm
The code shows on the digital display on the front panel. Energy and Betacom models display it without a separator, so you will see F22 rather than F.22.
How to reset a Glow-worm
Press and hold the reset button for around three seconds until the display clears. On Energy models the reset is the button marked with a flame and a cross beneath the display.
Most common Glow-worm faults
The Glow-worm codes people look up most.
- F.28Get it checkedIgnition was unsuccessful at start-up and the boiler has locked out. Check the gas and the condensate pipe before calling anyone.
- F22Get it checkedThe boiler has locked out because system pressure is too low to run safely. Topping up to 1.2 bar and resetting normally fixes it.
- F75Get it checkedThe boiler saw no pressure rise when the pump started, so it locked out. Almost always the pressure sensor or the pump, not low pressure.
- F1Stop — call an engineerNo flame was detected during ignition, so the boiler has shut the gas off and locked out. Two resets at most before calling someone.
Every Glow-worm fault code
7 published codes. Filtering happens in the page — every code is in the HTML.
Showing 7 of 7 codes
Glow-worm models
Codes can differ between generations. Check yours.
Guides that help with Glow-worm faults
How to repressurise a boiler
The five-minute job that resolves more no-heating calls than any other. Here is how to do it properly, and how to tell when topping up is the wrong answer.Read the guideWhat to do when your condensate pipe freezes
The single most common winter boiler fault, and one of the few you can genuinely fix yourself in fifteen minutes with a kettle and some patience.Read the guideBoiler fault codes explained: what they actually tell you
Codes look like diagnoses and are not. Understanding which family a code belongs to turns a meaningless number into a genuinely useful starting point.Read the guide
Looking for Glow-worm’s own support? www.glow-worm.co.uk. We are not affiliated with Glow-worm.