2 new radiators not heating up

[Mattycs]

Hi
ive moved house and had all the radiators replaced. They all work great apart from the two in my daughters room (which was an extension of the house before we bought it). They all have trv's fitted. I've turned all the other rads in the house off apart from these two and tried running it but nothing. They have both been bled. The lock shield valves are both open. The trv is not stuck. The pipe work runs into the room down to the first rad then off to the second then back out the room. The pipework coming into the room gets really hot leading to the first trv and heats up the rad slightly then seems to cool down. The pipe coming out of the rad doesn't warm in the slightest. Over the weekend I've took both rads off and placed a bucked underneath the trv and the water gushes out quite quickly until the pressure drops at the boiler. The boiler pressure is at 2bars. whilst the rads were off I poured water though them both which seemed ok.
Really stuck, as you may tell I've been offered lots of advice by different people but they're still not working and it's like as icebox in that room recently.
thankyou for any help

 

[townfanjon]

Micro bore ?

 

[Mattycs]

For the first metre or thereabouts its 15mm then yes it drops too 10mm around the room then back to 15mm on the way out

 

[townfanjon]

is that the first meter from where the tee was inserted into the existing pipe ? Its hard to say without seeing how far the lenghs are and if you are trying to run 2 rads off one 10mm feed rather than 2 seperate ones , you will be lucky if it works .
Just check the TRV's are bi-directional ( work on either flow or return ) Good luck

 

[Mattycs]

The pipe runs into the room for about 1 meter at 15mm. It used to then tee off at 10mm to each rad , as it never worked someone suggested that I try to change the tee to an elbow and run it in to one rad and off to the other rad then back out the room ??
Is there a way of checking the trv to see if it's bi-directional or would I need to contact the plumber to check ?
Thanks

 

[KingDoey]

On the valve there should be an arrow denoting flow direction. If it has two arrows i.e pointing both ways it is bi directional. Obviously not all valves will have this but you might be lucky...

 

[Riley]

Have you removed radiator and checked you have flow at both valves

 

[Mattycs]

I can't see any arrows on the valves, and yes when I had the radiator off water gushed out of both ends when opened, until the pressure dropped

 

[Mattycs]

Had another look there are two arrows as if you can have the trv either bottom entry or side entry ...
I've beeen advised to put the tee back on with 15mm .... so now there's only about a metre of 10 mm coming out and into the radiator and the rest is in 15mm
Still the pipe gets hot initially and the rad only slightly

 

[ShaunCorbs]

Had another look there are two arrows as if you can have the trv either bottom entry or side entry ...
I've beeen advised to put the tee back on with 15mm .... so now there's only about a metre of 10 mm coming out and into the radiator and the rest is in 15mm
Still the pipe gets hot initially and the rad only slightly

what trvs do you have ?