Glow-worm S.06 Fault Code
Also written as S06 — same fault.
The Glow-worm S.06 fault code means: your boiler's fan is continuing to run after it should have stopped, causing the system to pause for safety reasons.. It appears on 12 Glow-worm models in our database.
Technical description: fan overrun
What causes the Glow-worm S.06 fault?
This fault occurs when the boiler's control system detects that the fan is still spinning even though the heating or hot water demand has finished. The most common reason is a communication error between the fan and the main circuit board, or a sticking internal component that fails to cut power to the fan motor. For safety, the boiler will pause operation until it detects the fan has correctly stopped.
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 S.06 fault code
Click a model for the full fault code list and model-specific repair notes.
- Flexicom 18sx Repair: £150-350
- Flexicom cx Repair: £120-350
- Flexicom hx Repair: £150-350
- Flexicom sx Repair: £150-350
- Ultracom 2 CXI Repair: £120-350
- Ultracom 2 HXI Repair: £120-350
- Ultracom 2 SXI Repair: £120-£350
- Ultracom 24cx 30cx Repair: £120-350
- Ultracom 35 Store Repair: £120-350
- Ultracom cxi Repair: £120-350
- Ultracom hxi Repair: £120-350
- Ultracom sxi Repair: £120-£350
Source
Glow-worm S.06 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