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Glow-worm Micron 100FF Fault codes & diagnostics
5 fault codes with plain-English explanations, severity ratings, DIY guidance, and repair cost estimates.
Gas 2001-present
GC Number 41-047-52
Download the Glow-worm Micron 100FF manual
PDF
Versions & GC numbers
The fault code is already on your display
Note it down before pressing reset — resetting clears the code immediately. How to read fault codes →
Which version do you have?
The GC number on your boiler's data badge identifies the exact appliance and production years, as recorded in the UK Product Characteristics Database.
| GC number | Appliance (register name) | Produced |
|---|---|---|
| 41-047-52 | Micron 100FF | 2001–present |
Appliance names and production years are taken from the UK Product Characteristics Database (the SAP/SEDBUK register). Where a GC number is also printed in this model's own manufacturer manual, both sources were checked to agree.
Just want the most common Glow-worm Micron 100FF faults?
The top 6 problems in plain English — with causes, DIY checks and repair costs.
Fault codes
All 5 documented codes
Tap any card for details
Neon 1 not lit
Fault with mains supply or PCB fuse
Neon 2 not lit
Low water pressure (sealed system), Overheat cut off device tripped or thermostat, overheat cut off device faulty
Neon 3 not lit
Air flow proving fault - that is fan or air pressure switch
Neon 4 not lit
Ignition, pilot or flame proving fault
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