UFH - Multiple Floors - Single Manifold & Pump?

[minicooper13i]

Good afternoon all.

 

I've been doing a lot of research on how best to install UFH in my Victorian Terrace but have come across some conflicting information from a couple of the suppliers I've been in contact with.

 

Ideally, I would like to have a 10 port manifold and pump mounted centrally on the ground floor (cupboard under the stairs) near the boiler and rise the UFH pipework pretty much centrally to serve the two floors above (first floor and loft conversion).  One company says this is fine and has quoted accordingly, whilst the other has said it can't be done and I would need a pump and manifold for each floor.  I can't seem to find anything online to corroborate either opinion....

 

Obviously, having a manifold and pump on each floor would push the cost up significantly, not to mention casue extra hassle with the plumbing to / from the boiler, so I really want to go with just the one manifold arrangement.  I've not calculated loop lengths yet but this isn't a massive place; just a typical working class two up - two down terrace with one up - one down rear extension.

 

All informed opinions are most welcome.

 

Thanks very much

 

Graham

[ProDave]

No.  If a loop runs up hill from the manifold, it WILL trap air with nowhere to bleed it out and stop working.

 

It might work better if you really have to only have one manifold with it on the top floor and long runs down to the lower loops that will at least self bleed to be bleed points on the manifold.

[willbish]

Another thing to consider is if you're floor build up and insulation levels are different on different floors then you will require different flow temperatures for the same output.

 

I was going to do as @ProDavesuggested and have a single large manifold on the first floor, yes it would be cheaper for the hardware, but a single blending valve cannot deliver different temperatures.

 

Plan for two manifolds

[dpmiller]

I've one upstairs loop running from the GF manifold. I've a Tee at FF level on both flow and return with an autobleeder a few feet above on each. Flows fine, bleeds fine.

[PeterW]

9 minutes ago, willbish said:

Another thing to consider is if you're floor build up and insulation levels are different on different floors then you will require different flow temperatures for the same output.

 

Not needed if you use the Auto Balancing heads as they will balance flow and return to delta 7°C differential. 

 

9 minutes ago, dpmiller said:

I've one upstairs loop running from the GF manifold. I've a Tee at FF level on both flow and return with an autobleeder a few feet above on each. Flows fine, bleeds fine.

This works perfectly and all you need to do - just put the tees in accessible places so you can service the auto bleed valves. 

[willbish]

20 minutes ago, PeterW said:

Not needed if you use the Auto Balancing heads as they will balance flow and return to delta 7°C differential. 

 

Isnt it asking a bit much of the actuators if you only need a few degrees above room temp on the ground floor but something nearer 35° upstairs?

[PeterW]

Why would you..? deltaT from room temperature to water temperature is what causes the heat transfer - larger deltaT, quicker warm up. 

[Nickfromwales]

If there’s a ground floor then a 1st and then an attic conversion you deffo need 2 manifolds minimum. 
The ground floor manifold will service ground floor only, and the attic manifold can service that and drop to service the 1st floor. You’ll need an accurate loop length plan that takes into account the 2.6m drops and you’ll want to keep the loop lengths well under the preferred 100m max ideally.

The attic manifold will need a manual bypass valve across flow and return to allow the boiler pump to be hydraulically “free” when nearly all loops are shut. 
What is the heat source? Gas I assume. You’ll deffo need to factor in a buffer tank for when the house is up near / at the temp and the majority of actuators are closed. Retro fit high temp UFH is a recipe for short cycling and that will fatigue, and could cause early failure of, the boiler. It could also make it inefficient.

Save yourself some money and just fit a couple of radiators in the attic? If you insulate and address draughts then that space will need very little heat.