New low temp manifold system

[NandM]

I've been thinking about heating requirements for our refurb. I'll be going for a new system boiler + UVC and had an engineer around yesterday. As I'll be laying down 70-80mm on PIR for a floating engineered wood floor, he suggested using copper pipes embedded within the insualtion. I like the idea of embedding as it means no pipes down the wall...but don't like the idea of joints that could leak.

 

This lead me to the use of manifolds and a radial system - still embedded but with no joints. I was thinking about having two manifolds, one for the upstairs circuit and one of downstairs and to use one thermostat in the hallway on each on floor to act as the control for that floor...I don't plan on using TVRs on the rads. Does this sounds like a recipe for disaster?  (I'm looking at a Vailant Pure 625)

 

I'll also be oversizing the radiators to use them at low temperatures and the house will be insulated above regs (125-150mm IWI + 50mm CWI)  and made as airtight as is practical.

 

Is the use of a manifold setup for radiators something of a specilaist thing, or should more engineers be able to install it?

[JohnMo]

I wouldn't like to embed copper pipes as you say with joints, Pert-al-Pert or similar would be better, a manifold would be easy enough.  You could almost run it like UFH, but with radiators.

 

Assume the upstairs will be bedrooms, do you like the same temperatures in your bedrooms?  A thermostat in each bedroom, would enable you run slightly cooler temps in one or more rooms.

[NandM]

Upstairs will be bedrooms plus family family bathroom...and ideally a office - but I may have to stick that in the garden. Hadn't thought about run some rooms coolers - would that mean having an actuator for each outlet on the manifold for that floor?

[ValleyBoy1958]

Have you done an interstitial condensation calculation of that thickness of IWI? I only ask because I went through a similar exercise recently assuming 75mm Celotex as IWI and the calculation showed that there was no risk of condensation but 150mm might be a different kettle of fish!

[SteamyTea]

On 14/11/2021 at 15:52, NandM said:

I was thinking about having two manifolds, one for the upstairs circuit and one of downstairs and to use one thermostat in the hallway on each on floor to act as the control for that floor...I don't plan on using TVRs on the rads. Does this sounds like a recipe for disaster?

Reminds me of the system my Grandmother had (though she only had once circuit and the thermostat was in the cold hallway).  One advantage of using a manifold is that you can control individual circuits, relatively easily.

We have moved on since 1950.

Edited November 15, 2021 by SteamyTea

[NandM]

Hmmm  - not done the cals. I'll have a play about with this tonight: https://builddesk.co.uk/software/builddesk-u/condensation-risk/