9 fault codes with plain-English explanations, severity ratings, DIY guidance, and repair cost estimates.
Replaced by: CDi Classic
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 |
|---|---|---|
| 47-311-41 | 26 Cdi Xtra | 1998–2002 |
| 47-311-42 | 26 CDi Xtra RSF | 1998–2005 |
Tap any card for details
Your boiler has detected a critical internal communication or hardware error and has locked itself out for safety.
Your boiler is temporarily pausing because it has already reached the required temperature and is waiting for the water to cool down slightly before firing up again.
Your boiler's computer brains are having a communication problem because an incorrect or faulty internal component has been detected.
Your boiler's hot water sensor has failed or has a loose connection, meaning the system cannot accurately measure the temperature of the water coming out of your taps.
Your boiler has detected trapped air inside the system that is preventing the water from circulating efficiently.
Your boiler is failing to light the flame or keep it running, which means it cannot produce any heating or hot water for your home.
Your boiler's water pump is failing to move hot water around your system, meaning your radiators and taps will not warm up.
Your boiler has stopped working because it cannot detect a flame, likely due to an interruption in your gas supply.
Your boiler has lost power completely and the display screen is blank, meaning it cannot start the heating or hot water process.
Not faults — these are normal operating states. Tap to expand.
BoilerFaultCodes