BoilerFaultCodes
Pro Boiler Fault Codes
79 fault codes across 6 Pro boiler models — explained in plain English.
Pro / ProCombi boilers (Vokera/Ideal-built).
Pro fault codes on this site
We document 79 fault codes across 6 Pro models, covering 47 distinct codes. Pro boilers use letter-and-number codes such as AL10, AL20, AL21. Codes for 6 of these models are taken directly from the manufacturer's own service or installation manual.
Models covered: A28, ProCombi 100HE, ProCombi CT 25, ProCombi Exclusive 24, A32, A36.
Just want the most common Pro problems?
The top 8 faults across the whole Pro range — causes, DIY checks, repair costs.
High-severity Pro fault codes
low-pressure 10 AL10 AL20 AL21
Your boiler has stopped working because the water pressure inside the system has dropped too low to allow it to run safely.
A28
Your boiler has failed to ignite, which is usually caused by an issue with the gas flow or the air exhaust system.
A28
Your boiler has stopped working because it cannot light the burner, likely due to a gas supply issue or a blockage in the drainage pipe.
A28
Your boiler has switched itself off because it has detected that an internal component is overheating or getting too hot to operate safely.
A28
Your boiler has detected an issue with a safety device or an external thermometer, causing it to shut down to prevent overheating.
A28
All models
6 Pro boiler models
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