Glow-worm Fuelsaver Complheat 80 Fault codes & diagnostics

6 fault codes with plain-English explanations, severity ratings, DIY guidance, and repair cost estimates.

Regular Natural Gas 1991-2002 Discontinued

GC Number 41-319-18

The fault code is already on your display

Note it down before pressing reset — resetting clears the code immediately. How to read fault codes →

Severity at a glance

Each cell = one fault code. Hover to identify.

6 High

Fault codes

Tap any card for details

Check the pressure gauge on the front of the boiler or in your airing cupboard; if below 1.0 bar, top it up using the filling loop
Check your home's consumer unit (fuse box) to ensure the heating circuit hasn't tripped
Switch the boiler off at the wall, wait 30 seconds, and switch it back on to reset the electronics

Check that your pump is running and not stuck
Ensure all radiator valves are open to allow water flow
Once the unit has cooled, press the reset button located on the overheat thermostat (refer to manual for exact location)

Locate the external filling loop, which is usually a silver flexible hose with two small valves.
Open both tap handles slowly until you hear water flowing into the system.
Watch the pressure gauge until it reaches between 1.0 and 1.5 bar, then close both taps tightly.
The red light should extinguish and the boiler should restart automatically.

Locate the filling loop, which is usually a silver flexible hose with one or two small taps.
Slowly open the tap(s) until you hear water entering the system.
Watch the pressure gauge and close the taps firmly once it reaches between 1.0 and 1.5 bar.

Status & diagnostic codes

Not faults — these are normal operating states. Tap to expand.