Glow-worm Compact Fault codes & diagnostics

What to check first

1. Locate the filling loop (usually a silver flexible hose) underneath or near the boiler
2. Slowly open the tap or taps on the filling loop to allow water into the system
3. Monitor the pressure gauge until it reaches between 1 and 1.5 bar, then close the taps fully

Parts commonly replaced

• Low water pressure switch
• Filling loop
• Expansion vessel

What to check first

1. Turn the main On/Off switch to the '0' position
2. Wait for at least five seconds
3. Turn the switch back to the 'I' position to restart the boiler

Parts commonly replaced

• Ignition Electrode
• Gas Valve
• Printed Circuit Board (PCB)

What to check first

1. Check the external flue pipe (the white pipe on your outside wall) for any visible obstructions like bird nests, leaves, or debris.
2. Ensure there are no items such as garden furniture or plants blocking the airway of the flue.
3. If the exterior is clear, do not attempt to open the boiler; you must call a Gas Safe engineer to inspect the internal fan and air pressure switch.

Parts commonly replaced

• Fan assembly
• Air pressure switch
• Flue seals

What to check first

1. Check if other gas appliances, like a cooker, are working to confirm your gas supply is active.
2. If you have a prepayment meter, check that you have enough credit.
3. Locate your gas meter and ensure the main handle is in the 'on' position.
4. Reset the boiler by turning the main selector dial to 'Reset' for five seconds, then back to your preferred setting.

Parts commonly replaced

• Gas valve
• Spark electrodes
• Ignition lead
• PCB