Sunvic valve and heating/hot water issue

Calleja

Hi all,

Looking for some help from you very useful people out there....and please excuse my ignorance.

New house - I noticed previously I couldn't turn on the heating without the hot water. Niaively didn't think too much more about it, thought it was normal....testing out heating again and decided it probably wans't normal. On googling, I've come to the conclusion its my 3 port sunvic valve, not sure of the type but looks like this:
http://www.sunvic.co.uk/products/motorised-zone-valves/

On another thread it suggested forcing the valve whilst the programmer was calling for heat. Wasn't exactly sure how to do that, but I 'forced' the red part with a screwdriver...and now the opposite is happening i.e. everytime water comes on, heating comes on.

I'm guessing this is replacement part/gas engineer territory, but thought I would post on here, and ask everyones advice, to see if there is anything else I could do.

Cheers!

Southend1

It depends how your system is plumbed. Mine you have to have the hot water on to have the heating on but you can have hot water on with heating off.

Tiexen

I've had one of those fail - managed to swap the top electrical part from a new one leaving the plumbing side as it is.

Myser

If you remove the actuator (box on top), is the valve spindle easy to rotate or is there resistance?

Calleja

Thanks all, really appreciate it.

Myser - the box does have screws. Am I safe to just remove those and will that enable me to see the valve spindle and try to move it? I'm going to be away now for a few weeks (hence why I was trying out my heating for the house sitter) - whats the implications if I can or can't move it?

Thanks again - this site is a godsend for those without 'handy' people in their lives!

Calleja

Tiexen wrote: »

I've had one of those fail - managed to swap the top electrical part from a new one leaving the plumbing side as it is.

thanks for the reply. Did you manage to do this yourself? Is it safe for a novice to do?

keystone

Calleja wrote: »

Am I safe to just remove those and will that enable me to see the valve spindle and try to move it?

Yes.

whats the implications if I can or can't move it?

If it moves freely then its probably the head. If it can be freed up and the head operates it properly tyen nothing more to be done. If its totally imoveable you need a new valve body.

But you should also check the operation of the head. Take it off the valve but leave it connected electrically. Turn CH stat right down so that it isn't calling for heat. Operate the cylinder stat so that it is then isn't calling for heat for the cylinder. You should hear the motor operate and see movermnet whilst the head is trying to drive the valve round and then letting it settle again to the mid position. Turn tank stat right down and then repeat getting someone else to operate the roomstat. Then try a combination of both. If the head does everything it is supposed to do then its fine.

Cheers

keystone

Calleja wrote: »

Is it safe for a novice to do?

Yes you will have to disconnect the wires from the wiring centre to change it and connect the new one. It is live at all times so make sure its isolated first. And connect the wires for the new head in the same places you took the old ones from. Typically its like this: Either draw the connections of yours before you start or take a pic to refer to.



BUT - before you do that check the operation of the head as described above.

Cheers

keystone

There you go. Now you've had the same answer from two of us.

Cheers

ValHaller

Sometimes people put these valves in without entirely knowing what they are doing and either the plumbing or the wiring is not really configured to support independent operation of HW and CH ....

As you have never seen it working as you expect, you need to confirm that the system programmer will support CH and HW independently and you also need to check out the plumbing

Calleja

ValHaller wrote: »

Sometimes people put these valves in without entirely knowing what they are doing and either the plumbing or the wiring is not really configured to support independent operation of HW and CH ....

As you have never seen it working as you expect, you need to confirm that the system programmer will support CH and HW independently and you also need to check out the plumbing

Thanks ValHaller. Looking at the programmer manual, it seems to support use of CH/HW independently. The plumbing, on the other hand, I wouldn't have a clue.....any quick way of telling by looking? Apologies if its a stupid question!

If I do need a new one of these valves, can it be fitted by a plumber or does it need to be a gas safe engineer?

Thanks all!