What to do after draining a radiator

I've decorated a couple of rooms recently and removed the radiators in both cases. What I'd like to know is do I need to top up the system with either water or anti-corrosive, will it fill itself from mains, or will it have enough liquid in it anyway?
Thanks.

The Boilermate 2 has an expansion tank fitted on top of it. If this tank has a ball valve fitted to it, you need do nothing as it will top itself up, however, if it hasn't got a ball valve then you would need to refill it manually (until about half full).

It is always good practice to add some corrossion inhibitor after you have drained part of the heating system. Sentinel X100 or Fernox F1 ar my preffered chemicals and are readily available from all reputable plumbers merchants.

Excellent - I found the expansion tank so will check if it's refilled and get some additive for it.
Thanks for your reply.