Warmflow combi oil

[Chilly2]

Hi all I'm seeking some help please, I have Warmflow combi oil boiler KC70HE over the weekend it's developed a fault. So what's happening is the radiators are getting hot when they are not programmed to do so, I'm assuming that the hot tap water system is somehow feeding into the the radiator system via a failed valve or something any ideas will be much appreciated

 

[oilhead]

Check that the CH pump is not running. If it is, then meter out the wiring to establish the source of supply. If it is not, then there is a non return valve below the pump which may be jammed. How clean is the system water?

 

[Chilly2]

Thanks for your reply Oilhead the ch pump is not running, I can't see a non return valve below the pump and systems water is not too dirty

 

[oilhead]

The Non Return Valve is incorporated in the pump isolation valve. If you switch the boiler off, let it cool down and then start it up on hot water only, then you can feel the pipework in the boiler to track the flow of water as the heatstore heats up.

 

[Chilly2]

All sorted now I found a very small plastic non return valve inside the top of the twin pump that had jammed open allowing a back flow. Bought a new valve for 12 quid and popped it into the top of the pump and problem solved.

 

[oilhead]

All these twin pump combi's rely on these cheap non return valves. They do away with diverter valves and are easier to control ( and cheaper), but are unreliable and expensive to replace with labour costs. At least yours did not require full draindown, but the Firebird replacement is a complete isolation valve requiring drain down, which is a pain when no isolation is fitted to the flow and return.

 

[BoilerBob]

And the grant does to. Bob