Likely causes
- Pump failed, or air in the pump
- Pressure sensor blocked with sludge or faulty
- Expansion vessel has lost its charge
- Very low system pressure
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
- Bleed any radiators that are cold at the top, then check the pressure again
- Reset the boiler once
What our engineer does
We test the pump and pressure sensor, check the expansion vessel and clean or replace the part that has failed. 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.
