5 fault codes with plain-English explanations, severity ratings, DIY guidance, and repair cost estimates.
This boiler uses LED flash patterns
Count the flashes in one repeating group before the pause. That number is your fault code. Do not reset until you have noted it. 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 |
|---|---|---|
| 41-555-18 | twentytwentysix | 2000–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 currently in a normal waiting period and will start back up automatically in a few minutes.
Your boiler has temporarily stopped working because the internal drain pipe that removes waste water is likely blocked, often due to freezing during cold weather.
Your boiler has automatically shut down because the exhaust pipe has become dangerously hot.
Your boiler has switched itself off to prevent damage because the unit has become too hot.
Your boiler has detected that the incoming electrical wires are connected the wrong way around, preventing it from safely starting the main burner.
BoilerFaultCodes