Glow-worm Intermittent Lockout / Unstable Operation

Boiler frequently needs manual reset but no clear error code is shown

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Safety Warning

This repair may involve working with high voltage components or water connections. Always unplug the appliance before removing any panels.

If you are not confident in your ability to perform this repair safely, we strongly recommend contacting a professional technician.

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Possible Causes

Marginal gas pressure, Intermittent sensor connection, PCB starting to fail, Overheating due to partial blockage

How to Fix / Troubleshooting

Safety: Do not repeatedly reset a boiler that locks out; underlying faults must be found.

  • Record symptoms: Note when lockouts occur (heating vs hot water, weather conditions, time of day) to help diagnosis.
  • Check system pressure and vents: Ensure pressure is stable and radiators are bled.
  • Engineer tasks:
    • Check gas inlet pressure under load.
    • Inspect and test all NTC sensors and wiring.
    • Check for partial blockages in heat exchanger or filters.
    • Test PCB for intermittent faults.

Intermittent faults can be complex; detailed testing by an experienced Glow-worm engineer is recommended.

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Repair Difficulty

Hard 4/5

Required Part

Main PCB
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