Roger Mills wrote:
In an earlier contribution to this discussion,
Dave wrote:

I'm doing lots of overtime at work but also trying to redecorate the
whole house in my spare time. Over the last two weeks I've had three
radiators off the walls to paper behind them, so that's three
'radiators-worth' of water I've lost out of the system and needed to
replace over that period of time.
I'll not get any decorating done for the next seven days but then
I'll be taking another rad off for a couple of days. I suppose, to
cut the story short, I'll be losing nine rads-worth of water and
replacing it again over a period of about three months in total,
maybe slightly longer.
What should I do about inhibitor? When should I add it into the
system? How much should I add in, and where? I've got a couple of 5ml
syringes that I could use to squirt the inhibitor into the rads
through the hole where the bleed valve goes after reconnecting them
and before refilling them - would this be OK?

TIA
Dave

Is it a vented system? If not, what I'm going to suggest won't work -
but otherwise, it will.

When I drain a radiator for decorating, I save the water in a bucket
and then - when putting it back - tip the water back into the F&E tank
immediately before bleeding the rad. That way, the inhibitor is
preserved.

Good idea Roger but mine's a pressurised system so your method won't work
I'm afraid. Thanks anyway mate.