No Central Heating only - fine on HW and CH or HW only

[jackthom]

I want a multimeter looking at the boiler demand when this happens.

Not volunteering for a trip to Cheshire though.

 

[dilalio]

I want a multimeter looking at the boiler demand when this happens.

Not volunteering for a trip to Cheshire though.

Yep.


Nope.

 

[Wildeman]

That's the crazy thing. If circulation is so terrible through the heating system how do the radiators ever get at all warm in Heating/DHW combined mode?

Why is the pump continuing to run, circulating cool water, yet the boiler doesn't appear to make any further attempts to fire after the first one?

This is what I cannot get my head around when in Heating/DHW combined mode the rad's get red hot but the minute the valve moves to the Heating only position the pump continues to run until the controller turns the program off but it is only circulating cool water!!

This is a new valve and head so 4 cannot be faulty surely and I have checked that Port A is going to the Heating and Port B is going to the DHW. I would have thought a piping/circulation issue would lead to no or lack of heat in radiators in the heating/DHW combined mode.

 

[Wildeman]

I want a multimeter looking at the boiler demand when this happens.

Not volunteering for a trip to Cheshire though.

This has been checked by 2 separate electricians how could that voltage differ from when in Heating only mode to Heating/DHW combined mode?

Also to prove it is not the wiring if I have it in Heating only mode so the valve has Port B fully closed and only Port A open with the pump running if I remove the head from the valve (Port B still closed with only Port A open) and then using pliers move the valve (head still removed) towards the mid position the boiler instantly lights and rad's get hot!

I believe this proves it is not the wiring or valve at fault - please correct me if I am wrong.

 

[dilalio]

I would be taking off that valve body and checking the innards - just for piece of mind!