Boiler heating the primary circuit when no call for heat

[Sweedo29]

Hi, I have been working on a renovation of a property. We have installed an unvented cylinder heated by a Worcester Bosch system boiler. When testing and commissioning the work we noticed that the boiler was heating the primary circuit when there was no call for heat on the programmer.(heating or hot water ). We noticed that the primary circuit was being heated as the towel rails are connected to the primary. I'm suspecting a wiring fault? The controls were wired by a separate contractor so wasn't sure whether to call him back. Any response is greatly appreciated, thanks

 

[Dan Robinson]

If you are qualified to fit an unvented cylinder, this should be easy to sort out.

http://www.youtube.com/watch?v=jbreKn4PoAc

 

[Sweedo29]

I'm not qualified, I'm running the entire project, just wanted some advise as who I need to contact. Do I need to call the ( unvented qualified engineer) or the sparks who wired the heating controls. Both have been a nightmare to deal with and will not be working on any more projects. Just want to know the basics of the problem to get this job handed over. Thanks

 

[Tibbot]

3 possible causes. Incorrect wiring, external controls wiring link left in or faulty motorised valve head. All these only involve electrical work.

 

[Sweedo29]

Thanks for your help. Got another sparky, il call him in the morning and get him to have a look, cheers

 

[Dan Robinson]

Fair enough..... wasn't clear form your OP.

But sparkies are the last people to be doing this sort of thing. Not least because they won't have a G3 qualification and so, can't work on the system; but also because 99% of them have no idea how a heating system works, either hydraulically or electrically.

Are you sure they haven't left the zone valve lever in the manual/flushing position?