Glow-worm Boiler Error Codes: Full UK Guide (2025)
Complete UK breakdown of Glow-worm boiler fault codes — causes, fixes, and typical repair costs for Energy, Betacom, Ultimate, Flexicom and older models.
Glow-worm Boiler Error Codes: Full UK Guide (2025)
Glow-worm boilers — including the Energy, Betacom, Flexicom, Ultimate, and Easicom ranges — are common across UK homes in London, Manchester, Birmingham, Leeds, Sheffield, Nottingham, Bristol, and Leicester.
This guide explains the most common Glow-worm fault codes, what they mean, how to fix them, and typical UK repair costs.
Need urgent help or want to prevent breakdowns?
Most Common Glow-worm Error Codes
F1 – Ignition Failure
Meaning: Boiler cannot light safely.
Causes:
- Flame sensor fault
- Gas valve issue
- Low gas pressure
- Blocked burner
Typical UK Cost: £120–£320
F22 – Low Water Pressure
Very common in UK winter months.
Fix:
- Repressurise to 1–1.5 bar
- Bleed radiators
- Check for leaks
Cost: £0–£160
F28 – Failed Ignition (Common in Cold Weather)
Often linked to frozen condensate pipes.
Fix:
- Defrost pipe
- Reset boiler
- Check gas supply
Cost: £0–£120
F75 – Pump / Pressure Sensor Fault
Meaning: Pump not detecting pressure change.
Causes:
- Failing pump
- Blocked system
- Dirty sensor
Cost: £140–£350
Glow-worm Heating & Temperature Faults
F4 – Flow Temperature Sensor Fault
Fix: Replace NTC sensor.
Cost: £80–£160
F5 – Return Temperature Sensor Fault
Similar to above.
Cost: £80–£160
F14 – Overheat / Blocked Heat Exchanger
Often caused by sludge in older UK homes.
Fix:
- Flush system
- Replace pump
Cost: £150–£350
Gas, Fan & Electrical Fault Codes
F29 – Flame Loss
Causes:
- Low gas pressure
- Faulty electrode
Cost: £120–£250
F16 – Fan Fault
Requires engineer.
Cost: £180–£350
F61 – Gas Valve Failure
Cost: £200–£380
F62 – Gas Valve Fault (Communication Error)
PCB cannot read valve signal.
Cost: £250–£480
Frozen Condensate Faults in UK Winter
Glow-worm boilers commonly show F28, F1, F22 during freezing weather.
Fix:
- Pour warm (not boiling) water over external condensate pipe
- Insulate pipe
Cost: £0–£120
Glow-worm Boiler Repair Costs (UK 2025)
| Fault | Typical UK Cost |
|---|---|
| Low pressure (F22) | £0–£160 |
| Pump failure (F75) | £140–£350 |
| Ignition fault (F1/F28) | £120–£320 |
| Fan replacement (F16) | £180–£350 |
| Sensor replacement (F4/F5) | £80–£160 |
| Gas valve replacement (F61/F62) | £200–£380 |
| Annual service | £70–£90 |
Should You Repair or Replace?
Consider replacing if:
- Boiler is 12+ years old
- Repeated F1, F28, or F75 faults
- PCB and gas valve issues occur together
- Repairs exceed £500–£600
For long-term protection, consider:
Final UK Advice
Glow-worm boilers are reliable but prone to F1, F22, F28, and F75 faults — especially in winter.
To minimise breakdowns:
- Keep boiler serviced yearly
- Maintain correct pressure
- Clear outdoor condensate pipes
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