Keston Combi C36 error E03


I have Keston Combi condensing boiler model c36, it is 7 years old and nowadays it switches itself off daily displaying message/error code E03. I checked in user manual and it means: overheat lockout mode. Does anyone know what need to be replaced and what is the cost of doing it yourself/using Keston service?


Hi John

Your problem is either very simple to fix- check if the pump is not blocked or/and what may cause lack of circulation. Or it is sth much serious  and will require checking the whole boiler/system. If it is just a pump failure cost wouldn’t be high- as not more than 2 hours are needed to complete it plus the pump cost- use rather Keston service if you have no experience with repairing boilers yourself. If however the fault is more serious I would advice purchasing new boiler.