Likely causes
- Pump failure or poor circulation
- Air in the system or low pressure
- Blocked heat exchanger
- Faulty temperature sensor or a poor earth connection
What you can safely check
- Check the pressure gauge or display and top up to between 1 and 1.5 bar if it is low, then close the filling loop fully
- Let the boiler cool, then reset it once
- Check that the radiator valves have not all been turned off
What our engineer does
We check the pump, sensors, earth connections and heat exchanger and find the reason the boiler ran too hot. Anything involving the gas supply, gas valve, combustion chamber, flue, fan, PCB or heat exchanger must be left to a Gas Safe registered engineer and must not be attempted by the householder.
Models this applies to: Glow-worm Energy, Glow-worm Ultimate, Glow-worm Compact, Glow-worm Easicom, Glow-worm Essential, Glow-worm Betacom4.
Boiler repairs from £90
Diagnosis and a fixed price before the repair. Most faults fixed on the first visit. Gas Safe 925538.
Other Glow-worm codes
Guidance only. Fault codes vary by model and firmware; anything involving gas, the flue, the fan, the gas valve, the PCB or the heat exchanger must be done by a Gas Safe registered engineer.
