Vertical Radiator Flow

10 Feb 2008
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Kingston, London
United Kingdom
About 7 years ago I asked for help on flow in my system...

I lived with this last radiator giving mostly poor output but now all my other radiators have been renewed with brand new Drayton TRV4 valves. And still the last vertical radiator is not flowing enough. I originally thought my bypass valve was the problem but now I've discovered it might just be the flow is racing straight through the bottom of the radiator.

So is it true that vertical radiators (mine's 2.0m tall) need an internal diverter? Could my radiator have one but it has just been installed upside down?

The radiator is from Radiating Style and is 2000 x 435 with 8 vertical T shaped bars connected by two horizontal tubes at top and bottom. I have looked at the top and see a sticker marked "DIAFRAMMA". Perhaps it means this is the end with a diaphragm and should be at the bottom?

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Photos of your radiator (not sales/brochure adverts) to show connections and complete radiator will help the guys here diagnose poor circulation.

Did you ask the company you purchased the radiator from ? Some are just importers only with no tech advice or any link to the makers which are often in china.

Did it come with an installation diagram or instructions,post it here aswell.

Its very fixable,just supply photos of the vertical rad,they do differ in their installation method.
Here are some pictures


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At least your pipes on this rad are already on the side wall.

Had same prob last year with a different vertical rads and the pipework alteration was the only remedy,they get roasting hot after the alteration.
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Great. If there is a plug in the top that would explain the problem. I did think about a change to the pipes to put the flow in to the top right (the TRV is on the return). But if there is a hidden diverter would this stop the flow getting to the left hand side of the radiator?
"Identify diverter position"

The factory fitted diverter can be identified by a ‘diaframma’
sticker found on the underside of one collector. The radiator must
be hung with the diverter at the bottom. If this sticker is missing
simply look into both collectors, one will have a clear water way
and one will have a deliberate blockage, this deliberate blockage
is the diverter.

Your radiator is fitted upside down , not a big job to swap it round.
Needs a clean at the top/bottom though... have a word with the domestic engineer! :sneaky:
Seven years (with some support from this forum) to find out the solution is so obvious. I wonder how many vertical radiators are in the same state.

Must get on to the fitter to exercise a 7 year warranty!

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