Keston Combi 55 error E12

Hi All,

I have a combi boiler from Keston model 55. I bought it 5 years ago and no problem with it till today. It switched off, I restarted, but it constantly shows E12. What does it mean? Is it serious? Can I fix it myself?


Hi Ken

E12┬ámeans that “thermal fuse blown or flue overheat thermostat activated”. You will need to replace both. Detailed replacement procedure is provided here in the “troubleshooting” section, and spare parts can be bought in a shop, but you should remember that only qualified – GasSafe Registered people can work on boilers.