Flow and no return

[RoyWin]

My Son has a problem with rads not getting hot and we think it may be caused by either the flow or return pipework. He has 2 rad on his living room one is hot and one is cold. Fig 1 is how the pipe work is currently, both the flow and return have tee connectors feeding the rads, the first rad is hot and the flow pipe to the second is hot but not the rad. The return pipe from the first rad is hot up to the tee and of course the return pipe from the second rad is cold. Am I correct in thinking that the flow and return pipes should be staggered as shown in fig 2 or is it only the return that this would affect as the flow does appear to be ok. Your advice would be appreciated.
Roy

 

[SJB060685]

Did the troublesome radiator work in the past?
First make sure the rad valves are open and the radiator is bled.
Is it an open vented system? I imagine you have a blockage somewhere.

 

[Deleted member 120897]

Is it just the one radiator not heating up? Sounds like a balancing issue.

 

[RoyWin]

No, there is another rad beyond the second rad that is also not heating. Do you think the tee in the pipework would restrict the return flow?

 

[SJB060685]

No, there is another rad beyond the second rad that is also not heating. Do you think the tee in the pipework would restrict the return flow?

First things first. Did either of these rads used to work?

 

[RoyWin]

The rad valves are open and bled.

 

[RoyWin]

These have been added as he has had some building work. The first rad get hot but the other 2 are only warm, if that, so they are getting hot water but it appears not to be flowing.

 

[SJB060685]

Ok. It could simply be the radiators need balancing, which honestly should have been done by the installer.
What size are these radiators and the pipework feeding them? You could have an underflow proplem, or perhaps the boiler is now not man enough for the job.
First approach would be to try and balance them.

 

[RoyWin]

Ok. It could simply be the radiators need balancing, which honestly should have been done by the installer.
What size are these radiators and the pipework feeding them? You could have an underflow proplem, or perhaps the boiler is now not man enough for the job.
First approach would be to try and balance them.

Ok, I’ll try balancing the rads, the rad are tall rads about 400mm wide x 1500mm high the pipework is 15mm. I assume you don’t think it is a problem with the flow at the tee in the pipework?

 

[SJB060685]

Ok, I’ll try balancing the rads, the rad are tall rads about 400mm wide x 1500mm high the pipework is 15mm. I assume you don’t think it is a problem with the flow at the tee in the pipework?

At the moment I don't think so. It's much more likely to be a balancing issue but there are other possibilities. First try and balance the system so you have equal flow to all radiators. If you're unsure on how to do this there are discriptions on here or videos online, pretty straight forward though

 

[John.g]

If it is all 15mm then it will work to a fashion as long as pump head sufficient except that piping is cross connected but I suppose it should be 22mm with short 15mm rad tails?.
I have two bedroom rads connected some what like that, no problems, pump head with all rads (10) in service is 3M.

 

[RoyWin]

Yeah,

At the moment I don't think so. It's much more likely to be a balancing issue but there are other possibilities. First try and balance the system so you have equal flow to all radiators. If you're unsure on how to do this there are discriptions on here or videos online, pretty straight forward though

 

[RoyWin]

Yeah,

Ok, thanks for your help, let’s hope that’s all it is.
Cheers
Roy

 

[John.g]

Ok, I’ll try balancing the rads, the rad are tall rads about 400mm wide x 1500mm high the pipework is 15mm. I assume you don’t think it is a problem with the flow at the tee in the pipework?

Ok, I’ll try balancing the rads, the rad are tall rads about 400mm wide x 1500mm high the pipework is 15mm. I assume you don’t think it is a problem with the flow at the tee in the pipework?

The tall rads (5 FT high??) are probably "1/2" the problem, are they fitted with baffles with the flow/return connected at the right ends?.

 

[SJB060685]

The tall rads (5 FT high??) are probably "1/2" the problem, are they fitted with baffles with the flow/return connected at the right ends?.

Some need them yes, although I can't say about your particular radiators. The installer should have been aware of this.