8 fault codes with plain-English explanations, severity ratings, DIY guidance, and repair cost estimates.
Replaced by: Micron 2
The fault code is already on your display
Note it down before pressing reset — resetting clears the code immediately. How to read fault codes →
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 |
|---|---|---|
| 41-047-16 | Micron 30FF | 1999–2002 |
| 41-047-49 | Micron 60 FF | 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.
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Your boiler is trying to start but the flame isn't catching, so it has safely disabled itself to prevent gas waste.
Your boiler has switched itself off because it has reached an unsafe temperature and needs to be cooled down and reset.
Your boiler has shut down because it has detected it is getting too hot, usually caused by a blockage or a pump failure.
Your boiler is failing to light or stay lit, meaning it cannot heat your home or water.
Your boiler has sensed it is getting too hot and has shut itself down as a safety precaution.
Your boiler has switched itself off because it got too hot, likely triggered by a safety sensor to prevent damage.
Your boiler has switched itself off because it has reached an unsafe temperature, usually caused by a circulation issue or a temporary blockage.
Your boiler's internal computer brain has encountered a glitch or failure and is struggling to run its operating system.
Not faults — these are normal operating states. Tap to expand.
BoilerFaultCodes