Draining hot&cold systems-Info?

[keith666]

Hi, another job i'm looking for guidance on. I am refurbishing the kitchen/utility and want to replace both sinks (have done same thing before)
Problem is the "builder" hasn't fitted any shut off valves to either.
The house has cold water storage and hot water tank, do i shut off main cold inlet under sink? and drain system?
There are a few valves on the water tank in the loft but not tried them to see what they do yet.
should there be a valve near the hot water tank also? still to look in void underneath it.

Looking for what should be there and if there is any particular order in shutting off and draining any part of either system.
Thanks for any advice on this.

Cheers

 

[gas4you]

Should be a gate valve on 22mm cold fill to hot water tank. This will turn off all hot taps. Stop cock will shut off cold mains only. After turning stop cock off run hot tap until ball valve drops to let all water out of cold mains taps. Then turn off 22mm gate valve.

 

[keith666]

Thanks for info, if I wanted to fit TRV's to some rads, can I follow previous procedure and then drain rad system??

Thanks again

 

[gas4you]

no. You will need to turn off the 15mm gate valve that comes from the heating header tank. The previous gate valve is for h/w only.

 

[keith666]

Thanks again for info.

Cheers