Glow-worm · Current Glow-worm F-code boilers
F.70Device Specific Number incorrect, missing or incompatible
This code applies to Energy, Energy7, Ultimate3, Sustain, Betacom4. Fault codes narrow down the likely problem, but they do not replace a model-specific diagnosis.
What you can safely check
- Do not remove the boiler case.
- Record the full code and model, then arrange a Gas Safe registered engineer.
How an engineer may fix it
Follow the model-specific fault-finding procedure, test the indicated circuit or component, repair the cause and recommission the appliance.
Glow-worm presents these as a general current-code guide; verify applicability in the exact appliance manual.
Manufacturer source: Glow-worm UK — Boiler Fault Codes. Checked 15 August 2026. The appliance manual and an engineer’s on-site diagnosis take precedence. Never remove the boiler case yourself.