BoilerFaultCodesGlow-worm F.22 Fault Code
Also written as F22 — same fault.
The Glow-worm F.22 fault code means: your boiler has stopped working because the amount of water inside your heating system has dropped below the minimum level required to operate safely.. It appears on 17 Glow-worm models in our database.
Technical description: System pressure too low
DIY fix possible
Locate the external filling loop, usually a silver braided hose with one or two valves underneath your boiler.Slowly open the valves until you hear water flowing and the pressure gauge on the front of the boiler rises into the green zone (typically between 1.0 and 1.5 bar).Close the valves tightly to stop the flow and ensure the pressure gauge stays steady.
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Glow-worm models that show the F.22 fault code
Click a model for the full fault code list and model-specific repair notes.
- 30cxi Repair: £0-120
- 38cxi Repair: £0-120
- Betacom4 Repair: £80-150
- Compact Repair: £80-150
- Easicom3 Combi Repair: £80-150
- Easicom3 System Repair: £100-250
- Energy Repair: £80-120
- Energy System Repair: £80-150
- Energy7 Combi Repair: £80-120
- Energy7 System Repair: £80-150
- Essential Repair: £80-150
- Flexicom 24c / 28c Repair: £80-150
- MicraCom Repair: £80-150
- Sustain 12s Repair: £0-120
- Ultimate 3 25R Repair: £80-150
- Ultimate3 Combi Repair: £80-150
- Ultimate3 System Repair: £80-150
Source
Glow-worm F.22 fault code information on this page is sourced and cross-checked against the official Glow-worm service / installation manuals for each affected model.
Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 7 July 2026