BoilerFaultCodes
Unical Boiler Fault Codes
93 fault codes across 2 Unical boiler models — explained in plain English.
Unical Alkon domestic condensing boilers.
Unical fault codes on this site
We document 93 fault codes across 2 Unical models, covering 48 distinct codes. Unical boilers use plain numeric codes such as 08, 09, 14. Codes for 2 of these models are taken directly from the manufacturer's own service or installation manual. Unical is a smaller name in the UK market, and if you own one this is likely one of the few places its fault codes are collected in one place.
Models covered: Alkon C 28 HE, Alkon R 28 HE.
Just want the most common Unical problems?
The top 8 faults across the whole Unical range — causes, DIY checks, repair costs.
High-severity Unical fault codes
db Fd AF FR HL
Your boiler is having trouble measuring the temperature of your hot water, which usually means it cannot heat water for your taps and showers until it is fixed.
Alkon C 28 HE
Your boiler is failing to light the gas flame required to heat your water and home.
Alkon C 28 HE
Your boiler has detected that waste gases are not escaping correctly through the flue, so it has shut down to prevent them from entering your home.
Alkon C 28 HE
Your boiler has stopped working because it has detected that the main part responsible for heating your water is failing to transfer heat correctly.
Alkon C 28 HE
Your boiler has shut down because it has detected an unsafe build-up of heat inside the unit.
Alkon C 28 HE
All models
2 Unical boiler models
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