Imperial to metric radiator swap

[wv62]

I want to swap some old rads for nice new ones. The old are from back in the '70s when the house was built so are all imperial. One is simple enough, it's 3' so I should be able to get a 900mm in (15mm difference which I'm sure I can get away with with the play in the pipes). The awkward one is 5' (1525mm). Looks like my best bet would be 1400. This gives me 125mm to find. Unfortunately I doubt if the water will jump from the valves to the rad so I was thinking of using two extension pieces to fill the gap, one each side obviously . Would Screwfix extension piece (cat no 4972R) do the job? Also the rads are on outside walls. Is it worth pasting the reflective foil/foam to the wall first to stop some heat escaping through the wall ?

 

[lightning]

Get a 1500 and use extensions

 

[wv62]

I was looking in Screwfix for rads and they don't list 1500. I'll have a look elsewhere for 1500. If I use a 1500 what extension would you recommend? The same one I listed?

 

[endecotp]

Is it worth pasting the reflective foil/foam to the wall first to stop some heat escaping through the wall ?

Foil is of little use behind a radiator, because despite its name the vast majority of the heat from a radiator is carried by convection rather than radiation. Convected heat flow is not reflected from foil any more than a blast of air from a fan is reflected from a mirror.

A layer of foam will increase the insulation of that part of the wall but not by much.

 

[wv62]

Well, I got the 900x500 rad changed today. As expected things didn't go exactly to plan but not too bad. One valve was passing slightly but nothing a rag shoved in the hole couldn't cure. Whoever fitted it did a bodge job though. One valve was metric, one imperial so had to use one of the old stems from the old rad. Got to look for a 1500 x 500 at a reasonable price now. The current rad has got a novel bleed valve. It's a wood screw wrapped in PTFE screwed into the rad! I'm just glad I haven't had to bleed it yet