CH won't work on Auto but will when switched to manual

[usguvna]

I have Grundfos WB12, the hot water is fine, however, when the thermostat calls for CH I don't get hot water to the radiators. There a white box by the water heate with metal lever (not technical) which has "man"and "auto" on the front. When I push the lever up to "man" it seems to release water and I get heat but it does not last. The white box goes to the wiring box on the wall. I hope this makes sense to someone becasue I want to get heat via auto but it's not happening.

 

[tomy]

the white box is either a two port or three port valve, either it isnt getting a live from your programmer when you turn the thermostat on or this valve is knackered , it is usually the motor in this valve which has gone . Depending on the model of valve you can buy just the motor or sometimes the head seperatly then you dont have to drain the system

 

[usguvna]

Thanks. Where do you buy these valves?

 

[Softus]

Since you're obviously a gambler you could ask in Littlewoods.

Or you could diagnose the problem and be sure of the solution.

For example, have you determined whether or not the thermostat is working correctly? And the programmer?

 

[MarkBarl]

Give the guy a break Softus, it's his first post.

Usguvna, welcome to the forums. What Softus is trying to say, is before rushing out to replace the valve, let's run a few other tests to make sure that the problem is definitely there. Firstly, can you take a picture of the White box you were talking about, as well as the boiler controls, heating controller and thermostat. This will enable people to give specific advice for your components rather than just generic advice.

Details on how to post a picture to the forum can be found here