BoilerFaultCodesGlow-worm F.76 Fault Code
Also written as F76 — same fault.
The Glow-worm F.76 fault code means: your boiler has detected a failure in a vital safety sensor that protects the heat exchanger from overheating, so it has shut itself down to prevent damage.. It appears on 8 Glow-worm models in our database.
Technical description: The safety cut-out in the primary heat exchanger is defective
Engineer required
This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
Find a Gas Safe engineer
Search the official register for a qualified engineer in your area.
Gas Safe Register →Avoid the next call-out bill
A cover plan would handle faults like F.76: no call-out fees, no surprise bills.
Affiliate links. We may earn a commission at no extra cost to you.
Glow-worm models that show the F.76 fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Glow-worm F.76 fault code information on this page is sourced and cross-checked against the official Glow-worm service / installation manuals for each affected model.
Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 7 July 2026