I need to replace a zone valve. How do I get the old zone valve off and if I am draining the pipes of water, how do I get the water back in?

Any other things I should be thinking about?

Thank you

 

when you refer to "zone valve" do you
mean a gate valve that is responsible
for part of the water distribution in
the house?
If so is it copper?
if it is you will need to cut the old
one out and sweat a new one in with a slip
coupling.
if its threaded galvanized pipe you may get
lucky and be able to remove the section
of pipe on either side of the valve and
replace with cpvc or copper with die-electric
unions.or you can just cut one of the
pieces of pipe into and remove it, then
thread the old valve off and thread a new one
on,then replace one side with one of the materials above.