BoilerFaultCodesGlow-worm F.67 Fault Code
Also written as F67 — same fault.
The Glow-worm F.67 fault code means: your boiler's electronic control board is receiving a confusing signal regarding the flame, which has caused the system to shut down for safety.. It appears on 6 Glow-worm models in our database.
Technical description: Value sent back by ASIC is incorrect (flame slgnal)
What causes the Glow-worm F.67 fault?
This fault occurs when the boiler's internal computer receives conflicting information about whether a flame is actually present inside the unit. It is usually caused by an electronic glitch on the main circuit board or a faulty sensor that is incorrectly detecting heat when it shouldn't. Because the system cannot be certain if it is safe to fire up, it shuts down to prevent potential damage or gas issues.
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 →Glow-worm models that show the F.67 fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Glow-worm F.67 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 27 April 2026