Can I close upstairs rads before draining the system?

[Sprogginz]

I've been working on a few rads over the last couple of weeks and so I've had to drain the Combi system several times.

I've got one more rad to do and it's downstairs.

I'm just wondering, can I just close all the rads upstairs before draining the system or doesn't it work like that because of the air pressure? What if I just bled one small rad upstairs to let air in?

I'm thinking it might make the refilling easier but maybe it's more trouble than it's worth.

Thanks for any advice.

 

[simond]

Yes, you can. Putting lots of fresh water in a rad system, eg multiple refills will damage it.

Best limit drain downs and refills, get inhibitor in there.

 

[footprints]

Certainly can do it but remember to reset the lock shield valve (the one without a wheel head) to the same setting to maintain system balance. You do run a slightly bigger risk of air locks however.

 

[Agile]

I always drain the absolute minimum if working on part of a system.

This limits the amount of new oxygen brought in and retains inhibitor.

As said check how many turns to close the lockshield and only open it to the same position to retain the balance.

Tony

 

[Sprogginz]

Excellent!

Thanks guys, much appreciated.