replacing radiator valves - system off, yes or no?

[glenglen]

i hope this is a simple question.
do i have to drain the heating system to replace both in and out radiator valves.
i am attempting to replace them with more decorative ones.
if i do not have to drain the system, then i am tempted to do this. what should i expect. some excess water that will stop ?
thanks
glen

 

[Bahco]

Yes you will have to drain down that 'drop' if it is a downstairs rad.

Look in the 'look here first' topic above for advice to refill.

 

[glenglen]

hi Bahco, what do you mean, "you would have to drain down that 'drop'.."
the radiator is upstairs anyway

thank you

 

[Bahco]

Assuming sealed system (as always) drain down below the rad you wish to work on via a drain off point.

Make sure the rad you wish to work on is empty. Allow air into system while draining via the bleed valve or side cap.

 

[glenglen]

the radiator is actually off. only the pipes and valves remain. sticking up from floor.
i was wondering if i could simply, replace the existing valves with new ones, without draining the system. or maybe a little water would come out.

thanks

 

[Bahco]

Maybe a little water would come out.

About 1 bars worth which will give your ceiling a new colour.

Drain down!

 

[glenglen]

thanks for your advice
much appreciated