Radiator Capacity

[The Medway Handyman]

Been trying to find the water capacity of standard radiators, not much online. Anyone know how much water a 1000mm double rad would hold?

[Andy Hall]

Some manufacturer data sheets give capacities in litres per section for different radiator sizes. You multiply by number of sections to get the total.

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.

[The Medway Handyman]

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.

[John Rumm]

You could make a secondary interceptor bin... 30l bin say with a tight fitting lid and an in and out connection for the vacuum at the top.

[Neil]

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.

Neil

[Andy Hall]

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.

[R]

Freezer kit, Freeze the rad corner and pipes, Replace valves, Move on to next rad

[Martin Pentreath]

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 combis!

[Martin Pentreath]

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.

[nightjar]

Freezer kits are expensive and IME only work reliably when you can get the sleeve to fit well, which usually means in the middle of a straight run of pipe.

Colin Bignell.

[John Rumm]

A dry board marker pen is handy here. Just write the number of turns of the lockshield valve down on the rad itself. Just rubs off later when you restore the previous setting.

[Man at B&Q]

And that the replacement rad is identical.

MBQ

[The Medway Handyman]

Good idea, but it was hard enough finding space in the van for the vac!

[The Medway Handyman]

I think the point is 'was the customer happy with it as it was'? Balanced or not.

I just return it to where it was.

[The Medway Handyman]

Cheapest I've seen pipe freezer kits is £7:61 from Toolstation, two per rad makes it an expensive way to do it. 6

[John Rumm]

Choose the bin side carefully, and you can keep the vac in it when on the van. ;-)

[R]

Agreed, the "can" system is crap. Hire one from a hire shop with the larger CO2 bottles and a fed pad that attaches to the CO2 hose.

Worked for me