One pipe system special rad valves

[Matt0029]

Are rad valves used on a one pipe system usually specialist less flow restrictive to normal valves? Possibly have a bathroom rad to swap for a towel rad. On one. Also can a modern towel rad. Be too flow restrictive for a one pipe system?

 

[Gasmk1]

you need full flow valves really

 

[ShaunCorbs]

Tbh lockshield valves only don’t tend to fit trvs

 

[Matt0029]

It's got trvs on at the moment. Not sure if full bore. But should a towel rad. Work OK on a one pipe system?

 

[Matt0029]

It's one of the first rads on the loop. But for any reason could the flow just carry on around the loop pipe and not go to the rad?

 

[Gasmk1]

It’s possible a modern one may not work as it may need top entry bottom return,

 

[Matt0029]

Thanks all the other rads are bottom feeds and bottom returns. I am trying to persuade the customer away from the idea.

 

[AWheating]

Should work if it's s standard towel rad. Avoid any which require the flow on a specific connection. As for valves standard valves will work but avoid things like Drayton trv as the have those small holes which may be yo restrictive. I'd use standard straight lockshields out of the floor. Sweep tees can be brought for around 5-6 quid.

 

[Matt0029]

Should work if it's s standard towel rad. Avoid any which require the flow on a specific connection. As for valves standard valves will work but avoid things like Drayton trv as the have those small holes which may be yo restrictive. I'd use standard straight lockshields out of the floor. Sweep tees can be brought for around 5-6 quid.

Thanks there also interested in a vertical collum radiator around 400mm wide 1000 to 1500mm heigh. Any chance of this working?

 

[Matt0029]

Or is there a reason one like this wouldn't work on a one pipe system

 

[Basher]

Fitted a tall radiator in our bathroom (not that brand) on our one-pipe system, and it didn't want to heat. Finally I 'throttled' the straight through pipe to divert water into the radiator, and of course it worked fine. Not too much of a problem for us as this 'zone' of our system only feeds one other room.
I would be wary of whether this is going to work For you.

 

[Matt0029]

Thanks why do the tall ones tend to struggle on a one pipe system? Putting a valve on the straight through pipe many not be great as there will be no access to the pipes underneath the floor afterwards. Laminate going down.

 

[Basher]

Thanks why do the tall ones tend to struggle on a one pipe system? Putting a valve on the straight through pipe many not be great as there will be no access to the pipes underneath the floor afterwards. Laminate going down.

You could use one of the Caleffi one-pipe valves, where you don't have a 'straight-through' pipe (other than what goes on inside the valve), so nothing needed under the floor, not even a pipe! The thermostatic version effectively acts as a diverter. There are other styles, and other brands.

This is the sort of thing I was thinking of:

https://www.caleffi.com/sites/default/files/file/01323_en.pdf

but not sure how well this might work with a tall rad!

 

[Matt0029]

You could use one of the Caleffi one-pipe valves, where you don't have a 'straight-through' pipe (other than what goes on inside the valve), so nothing needed under the floor, not even a pipe! The thermostatic version effectively acts as a diverter. There are other styles, and other brands.

This is the sort of thing I was thinking of:

https://www.caleffi.com/sites/default/files/file/01323_en.pdf

but not sure how well this might work with a tall rad!

Why is it that tall rads. Struggle on a one pipe system? Is it because the water isnt pumped through the rad. It relies on convection?

 

[Basher]

Why is it that tall rads. Struggle on a one pipe system? Is it because the water isnt pumped through the rad. It relies on convection?

It is indeed claimed that circulation is due to convection, but I would have thought if that's the case, a taller radiator might work at least as well as a short one. I don't know enough about fluid dynamics to answer.