Replacing a 2-port zone valve

[adamski4]

Hi All,

This is my first post so apologies if i miss out anything obvious. I've got a problem with my central heating at the moment that i've narrowed down to either the 2-port zone valve or the actuator thats attached to the top of it. To be honest i think its the valve as the actuator appears to turn correctly when its removed from the valve and i put the central heating on.

The replacment valve i've identified is on the link below, its a 22mm 2-port valve body and in that respect i've happy that i'v e identified the right bit.

The link is below and it will have a ZA6 actuator attached.
http://www.heatingcontrolsonline.co.uk/acl-drayton-invensys-6792-22mm-2port-valve-body-p-327.html

My question is how to actually go about doing the job. When it comes to pipework i am fine, its just that i worry about what to turn off, or to drain and all, i would really appreciate some guidance here before i pull my hair out (whatever is left anyway....)

Cheers,
Adamski4.





http://www.heatingcontrolsonline.co.uk/acl-drayton-invensys-6792-22mm-2port-valve-body-p-327.html

http://www.heatingcontrolsonline.co.uk/acl-drayton-invensys-za6-actuator-p-318.html

 

[superdupergasman]

I would normally use bungs when changing a 2 port valve on an open vented system ( one with a small header tank in the attick) for this you block open vent (expansion) and the cold feed (cold water into system). then crack the couplings on either side of the valve and catch the water that comes out in a bucket.

This process saves you the hassle of draining, refilling and getting airlocks all over the place.

However if you have never done that before it may be simpler to drain the whole system: Turn off water supply to header tank, open drain point, open upstairs bleed points and wait as the whole system drains. Remove 2 port valve and refit then refill after shutting your drain and vent points. then going round the system, bleading of air.

When also doing this make sure all electrics are isolated properly... remove fuse from the spur just to be on the safe side!

I am sure there is a guide of draining and bleeding in the FAQ at the top??

Have fun!

 

[adamski4]

Thanks there for the quick reply, its settled a few butterflies. As a rough guide, how long would you set aside for this sort of work?

 

[superdupergasman]

I would say for a first timer, a morning..... this way it gives you the afternoon to phone a friend if it goes pete tong!

If you are bunging tho it can be done in 20mins but you must be careful.

 

[gas4you]

Whats the fault with the valve?