New radiator isn't getting hot...

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Hi all, I installed a new radiator over the weekend but to my disappointment it isn't getting very hot!
It's a type 22 radiator 600x1600mm and fed with 10mm plastic pipes which drop down through a stud wall. The pipes feeding the branch are 15mm, which themselves are branched off 22mm pipes running through the middle of the house upstairs.

OK, first thought might be that the 15mm branch should be 22mm, but there's another radiator attached to the 15mm branch which is red hot. Here's a photo - you can see the 10mm pipes going downstairs, and the 15mm copper leads to the other radiator(the one that gets hot) which is the other side of the wall.

DSC_0001.JPG


The radiator downstairs is fully bled, available and I'm as sure as I can be that there are no kinks in the pipes feeding it. It does get reasonably hot but only at the top whilst the bottom is luke warm.

My conclusions are that the 15mm branch isn't the problem, as otherwise the other radiator wouldn't be getting so hot, so perhaps the issue is the 10mm pipes?

Any thoughts and/or suggestions?

Many thanks.
 
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FYI I have turned the valves off on the other radiator which is getting hot, but so far it doesn't appear to have made much difference :(
 
turn off ALL the other radiators.

If that fixes it, you need to balance all your radiators.
 
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For that size of rad I'd recommend 15mm flow and return.
 
For that size of rad I'd recommend 15mm flow and return.

Yeah that's what I was fearing!

I tried turning off all the other radiators and it did get a lot hotter.

So, now I've turned them back on again - the closest to the boiler I've only turned on a little (by the lockshield), the furthest away including this one I've put on full, and as a result it is hotter than originally although not as hot as when all the others were completely off.

Is there anything more I can do? Was hoping this beast would be pumping out some serious heat !

BTW the radiator in question is directly under where you can see the pipes dropping so they're max 3m each - does that matter at all?
 
10mm plastic is fairly restrictive, search the forum and google for balancing rads, its a bit more work than turning a rad near the boiler down a bit, but it may well make the difference.

the 15mm pipe upstairs, how many rads does it feed?

for a 1600 long rad I wouldnt go under 15mm either, but you can make a big difference with some balancing.
 
10mm plastic is fairly restrictive, search the forum and google for balancing rads, its a bit more work than turning a rad near the boiler down a bit, but it may well make the difference.

the 15mm pipe upstairs, how many rads does it feed?

for a 1600 long rad I wouldnt go under 15mm either, but you can make a big difference with some balancing.

Thanks, will have a look into proper balancing. The 15 mm pipe upstairs currently only feeds this radiator and the one the other side of the wall, but in the future it'll serve a downstairs toilet as well, but that'll only be a small towel rail or something.
 
Microbore systems can work well with 10 mm tube. Also many have just 8 mm tube.

But the difference from yours is that a microbore system is virtually self balancing because all the rad pipe routes are high resistance.

On a mixed system like your it should work well but only if its very carefully balanced. That needs skill and a few hours as every adjustment takes 10-15 minutes to stabilise.

A pipe thermostat is also useful too. This is one of the very few applications for an IR thermometer.

Tony
 
Microbore systems can work well with 10 mm tube. Also many have just 8 mm tube.

But the difference from yours is that a microbore system is virtually self balancing because all the rad pipe routes are high resistance.

On a mixed system like your it should work well but only if its very carefully balanced. That needs skill and a few hours as every adjustment takes 10-15 minutes to stabilise.

A pipe thermostat is also useful too. This is one of the very few applications for an IR thermometer.

Tony

Thanks Tony, i'll get myself a digital thermometer and try balancing them out properly before doing anything drastic like pulling down the stud wall and replacing with 15mm pipes!

I've been reading this guide - http://www.homebuilding.co.uk/2009/02/11/how-to-balance-radiators/ - any good? Also, will any digital thermometer do?
 
This site has good instructions in the FAQ on balancing.

You will save a lot of time if you set each lockshield valve just 1/2 turn open before you start. Then make adjustments of only 10 degrees of a turn at a time as they are very sensitive indeed. Wait 10 -15 minutes after each adjustment for the temperatures to stabilise.

The proper tool is a two input digital thermometer with contact thermocouple sensors so that the differential temperature can be seen.

But for DIY balancing a cheap IR thermometer can be used. They are seriously inaccurate because of the emissivity of the surface. But for this application its only the relative temperatures that are needed so they work fine.

Just point it at each lower end of the rad where the valve is fitted.

Ideally your rads should be balanced for a 10 C differential with a non-condensing boiler and 15-20 C for a condensing boiler.

Tony Glazier
 
This site has good instructions in the FAQ on balancing.

You will save a lot of time if you set each lockshield valve just 1/2 turn open before you start. Then make adjustments of only 10 degrees of a turn at a time as they are very sensitive indeed. Wait 10 -15 minutes after each adjustment for the temperatures to stabilise.

The proper tool is a two input digital thermometer with contact thermocouple sensors so that the differential temperature can be seen.

But for DIY balancing a cheap IR thermometer can be used. They are seriously inaccurate because of the emissivity of the surface. But for this application its only the relative temperatures that are needed so they work fine.

Just point it at each lower end of the rad where the valve is fitted.

Ideally your rads should be balanced for a 10 C differential with a non-condensing boiler and 15-20 C for a condensing boiler.

Tony Glazier

Great stuff, many thanks for your advice, will post back once i've properly balanced them...
 
If your using cheap ir thermometer get white masking tape and stick to whatever pipes your taking a reading from, this does away with the emmisivity issue and give a nice accurate reading (not required on the plastic pipes as it should read them fine)
 
I advise taking readings using an IR thermometer from the radiator surface as I described above.

That avoids any problem from trying on a pipe which is very narrow.

But the contact type you have bought is better.

A simple addition is a couple of clothes pegs with thick cloth/velvet glued to one face. That is used to hold the thermocouple junctions against the pipes.

Tony
 

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