8 fault codes with plain-English explanations, severity ratings, DIY guidance, and repair cost estimates.
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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 |
|---|---|---|
| 41-283-35 | Simplicity 20T | 2012–present |
| 41-283-36 | Simplicity 25T | 2012–present |
| 41-283-37 | Simplicity 30T | 2012–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 has detected a general internal fault that requires a professional inspection to determine the exact cause.
Your boiler has detected an internal fault that it cannot resolve itself and has locked out for safety.
Your boiler has detected an internal electronic error that requires a professional to reset and inspect the system.
Your boiler has encountered a critical system error that requires a professional manual reset and internal diagnostic check to function again.
Your boiler has encountered a system-level failure and has stopped working entirely to ensure safety.
Your boiler has encountered a deep-seated system error or sensor failure that requires a professional engineer to diagnose and reset.
Your boiler has detected an internal electronic error or a component failure that requires a professional inspection to restore normal operation.
Your boiler has detected an internal technical error that requires a professional diagnosis to safely reset and repair.
BoilerFaultCodes