Some manufacturer data sheets give capacities in litres per section for
different radiator sizes. You multiply by number of sections to get
Obviously it's height dependent as well.
At any rate, you can reasonably scale from one brand to another.
If this is to work out how much inhibitor is needed then don't forget
the pipe volume as well.
Reason I ask, I been getting a lot of jobs to 'remove/replace/move/ fit aTRV
to' radiators lately. Plumbers can't be arsed to do it. Bought a
Wickes/Earlex wet/dry vac to assist. Faster & cleaner job.
System I've adopted is to shut off all other rads by closing both valves,
suck water out of rad/pipe I'm working on.
Drain valves on CH systems are useless, far too slow to drain & the bastards
leak like pigs.
By leaving all unaffected rads full & just draining the specific rad &
pipework it makes the job faster & easier to bleed the system.
Trouble is the vac only has a 12l capacity, so I don't want to be in the
situation of it filling & the rad/pipe not being empty. If I knew the max
capacity of a large rad I could stop & empty out.
From: "The Medway Handyman"
Sent: Wednesday, November 07, 2007 9:56 PM
Subject: Radiator Capacity
Blimey after 3 years lurking one I can answer nearly...
Just taken out some 21/24" high by 6 to 8' - very old roll top singles and
these are one and two buckets in volume - the bucket in question is an
orange B+Q so you need to be emptying the 'hoover' on some jobs I suspect.
Ah, I see. The challenge would be not to get sludgy water on the
Axminster or the cat.
Except then you have to rebalance the system...?
Which is ridiculous, but the way it usually is. There are reasonable
ones with O rings that generally don't, but these cost a few pence more
and don't seem to get fitted.
Then I think that you could make up a ready reckoner using a
manufacturer data sheet to produce a simple printed list based on
width, height and a number of panels. For the flat steel ones,
there is not a wide variation between brands. It should be good
enough for this purpose.
Can you freeze the rad corner?
Agree that freezing is the easier way, but it gets expensive when you
need two freezing cans per rad (plus more for freezing corners?), and
there's not always enough pipe sticking out of the floor to be
confident about freezing it.
I've read on here about clever people putting a bung in the outlet for
the header tank which magically means atmospheric pressure holds the
water in the pipes - never had the nerve myself, and no good for
I've never met a "real" plumber who can be bothered with fiddly things
like balancing the system! Not properly at least, if you're lucky they
might spend 60 seconds just choking off a couple of rads closest to
the boiler, but there won't be a pipe thermometer in sight. Although
this is not to say balancing shouldn't be done. You can just note down
the quarter-turns needed to close each lockshield and then restore the
status quo later, although this does assume that the system was
balanced in the first place.