What is the correct orientation of a tee in a flow return circuit?

[Kevin Hattam]

Hi all,

I suspect I've incorrectly used a tee in the flow return as the two radiators don't seem to get hot enough.

I have two radiators and their flow returns feed into opposing ends of a tee.

Like below.

Rad ----|---- Rad

Return​

I think it should be like -

Rad -------|------- Return

Rad​

Hope that makes sense. Appreciate any advice thanks.

 

[Scott_D]

I'm confused
Any pictures

 

[Sharp Point]

It doesn’t really matter. Can you describe your situation in more depth, have you installed an additional rad to the circuit? What size are the pipes?

 

[Kevin Hattam]

So yes, I added an additional radiator about a year ago. The pipes are all 15mm. I drained down the system yesterday to replace the trvs as I initially thought they maybe the issue. When I refilled the system and switched on the heating the radiators we're very hot but then seemed to cool a little. Maybe I need to test this more.

 

[Kevin Hattam]

Hopefully the attached image will help. The left side of that tee is the return from the other radiator.

 

[Sharp Point]

Try turning off all radiators in the house, bar those two and then put the heating on

 

[SimonG]

Column style rads? And you did pipe the flow and return the right way round. Some of those rads need a definitive flow and return.

Or you did use bidirectional trv's.

 

[Kevin Hattam]

No they aren't column style radiators. Yeah I'm sure they are the right way around.

I'll try that, @bogrodder

 

[Sharp Point]

Column style rads? And you did pipe the flow and return the right way round. Some of those rads need a definitive flow and return.

Or you did use bidirectional trv's.

That’s a very good point, I forgot to add.

 

[Scott_D]

No they aren't column style radiators. Yeah I'm sure they are the right way around.

I'll try that, @bogrodder

So they are directional rads?

 

[Kevin Hattam]

Bidirectional as the only requirement was that the bleed valve was the opposite side to the flow in.

https://www.bestheating.com/media/pdf_files/STEEL_HORIZONTAL_radiators_ML.pdf

 

[Riley]

Do you have 15mm feeding two radiators??

 

[Welder]

10:1 its a balancing issue...

 

[Kevin Hattam]

@Riley yeah 15mm split to feed 2 radiators.

Like - https://www.diydata.com/planning/central_heating/twopipe3.gif

 

[Riley]

What’s the BTU/KW out out of the two rads