Only need central heatig not water Ideal icos 15

[Bilbopup]

As my hot water is from solar I only need the 'central heating' on. But now I find the boiler will only fire up and the central heating work if the 'domestic hot water' is turned on too. It has been fine before but now when I need heating on more it refuses to fire up unless the hot water is 'On' too. That defeats the object of having the solar. I am thinking a valve has stopped working? I don't get any fault codes, it just turns off!! Help please.

 

[jackthom]

Is there a 3 port valve in the system? Some pictures would help if poss.

 

[FiremanT]

Is it an oldish mechanical programmer?

 

[Bilbopup]

Is it an oldish mechanical programmer?

Well it's about 10 years old. A Drayton LP522 you should be able to programme HW And central heating separately.

Is there a 3 port valve in the system? Some pictures would help if poss.

Have put pics above, not sure if either is a three port

 

[Bilbopup]

Is it an oldish mechanical programmer?

Well it's about 10 years old. A Drayton LP522 you should be able to programme HW And central heating separately.

 

[jackthom]

Looks like a 2 port valve, are there two of them? If so the one for central heating is probably opening at least partially but not switching on the boiler as it should when it is fully open.

It could be a sticky valve or the microswitch inside could be dodgy.

You could try helping it to fully open by pushing the lever on the side and see if the boiler then fires up on CH only.