main burner operating High

Glow-worm main burner operating Fault Code

Also written as MAINBURNEROPERATING — same fault.

The Glow-worm main burner operating fault code means: your boiler's electronic control system is stuck in an error state while trying to fire up the main burner, meaning it cannot safely provide heating or hot water.. It appears on 1 Glow-worm model in our database.

Call an engineer soon

Book a Gas Safe engineer within 24 to 48 hours. Your boiler may be unsafe or could break down completely if left.

Technical description: Multi-functional control/harness problem
Typical repair cost £150-350 (including labour)

Engineer required

This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.

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Glow-worm models that show the main burner operating fault code

Click a model for the full fault code list and model-specific repair notes.

Source

Glow-worm main burner operating 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