No hot water unvented system

[Lozzie7]

Hi

My first post so please bear with me !!

I have an unvented water system and currently no hot water. The rads are heating ok but water stone cold.

There is a Grundfos pump near the tank which is quite noisy and gets very hot when the water is turned on for heating at the boiler.

I have bled all rads and turned the valve at the front of the Grundfos pump (a little water came out) but it hasn't made any difference.

I left the heating and water on last night on the off chance that we would have hot water this morning, but no!!! The rads were extremely hot this morning though, much hotter than they would normall be.

Any ideas??? (just to mention as well that the immersion doesn't heat up either when switched on at the wall, though we don't think it ever has).


Thanks

Laura

 

[ChrisR]

You'll have a motorised valve which opens when there's a call to heat the HW. Yours may not be opening.
It'll have a lever on it to latch it open manually, see the FAQs - search on "motorised".
Then your HW should get hot when the heating's on at least.
Would need a new motor, head or valve.

If you can see something high which looks deigned to let trapped air out, loosen and see... though releasing air at the pump which you have done, would probably remove trapped air as the main cause.

Check the boiler system pressure gauge, should be about 1 bar, depending...

 

[Lozzie7]

Hi

Thanks for your reply. I wll have a look through the FAQs.

 

[Lozzie7]

'blonde question'

Is the valve you refer to a white box attached to the pipes? I have two of them (says valve actuator code on front). They have a sliding black switch on the top and a button on the side.

I just pushed one of the switches from right to left, it then 'motored' back to the right again and now I can hear the pump working. It stopped pumping after about a minute. Is that normal?

Thanks

Laura

 

[Lozzie7]

Also, just put the heating on and the bottom valve is now stuck on the left hand side and won't move back