Mixer shower on unvented system

[Neil T]

Hi,
I need to replace a shower mixer valve on an unvented system, and as it's concealed there are no isolated valves. Is there anything specific I have to do to system to isolate h/w or is it just like a standard g/fed system and shut cold off and h/w feed on cylinder?
Cheers

 

[ShaunCorbs]

just turn cold mains off and drain down and then follow mis if its a megaflow for refilling

 

[Neil T]

OK thanks for that

 

[Neil T]

Would there be a valve on h/w flow from cylinder that I could just turn off rather than drain cylinder? I've done that on g/fed systems but need to check as it's unvented and don't want to bugga system up. Also do I have to isolate the elecs to cylinder?

 

[ShaunCorbs]

Would there be a valve on h/w flow from cylinder that I could just turn off rather than drain cylinder? I've done that on g/fed systems but need to check as it's unvented and don't want to bugga system up. Also do I have to isolate the elecs to cylinder?

If direct yes if indirect just turn programs off and you will need the cold off so just easier to turn mains off

 

[Neil T]

Cheers for your help