UFH Old Single Pipe CH System

[Onoff]

I've a 1930's extended bungalow. Due to a succession of add ons I have 4 different ground levels and at least 5 different floor make ups from suspended floor over dirt to the bathroom I dug down that has 175mm pir under a 100mm reinforced slab with 16mm UFH pipes in. Other are uninsulated slabs, joists atop slabs, it's a real hotch potch.

When I gutted the bathroom I put in a UFH loop on 16mm Pex-Al-Pex and a towel rad again fed by 16mm. As yet these aren't connected to anything.

Downstairs the CH is an old single pipe system. 3/4" nominal bore copper like the first diagram. Upstairs are 4 rads on a flow return set up.

Each system is on its own 2 port valve with the returns commoned up. Same pump is used for both.

So roughly this:

https://flic.kr/p/2aWLDWW

When I gutted the bathroom I removed the perimeter, single pipe. That now crosses the stairs room roughly where the green line is, goes up the hall and reconnects to the single pipe run behind the WC.

I'd like to feed my UFH loop off of the single pipe system. I can't connect it direct as the water temperature will be too hot. Best I can think of is fit a proper UFH manifold and involve a buffer tank. But how to blend? There's no separate flow & return.

Random sketch / thought for a separate buffer:

Running a new flow and return downstairs is a bit involved at the mo but might be the only way to go.

Any clever ideas?

 

[waddycall]

The manifold should have its own thermostatic blending valve using the return to temper the flow

 

[Onoff]

The manifold should have its own thermostatic blending valve using the return to temper the flow

Thanks but I don't have a proper return pipe downstairs. One option might be to tap into the upstairs circuit's return as it all end up at the same point?

 

[addjunkie]

You need something like this for UFH, and two loops in each room.

Grundfos Manifold Pump & Esbe Mixing Valve Unit

The ESBE compact T4 thermostatic 4-port pump set is suitable for a maximum output of 18kW. Features include 20 C-55 C temperature range suited for

www.fastwarm.com

 

[Kayos]

Connecting into a one pipe system the way you suggest simply will not work, needs a proper flow and return to the blending valve. Connecting upstairs and down will have an affect on the flow

This really is a time to do it properly

 

[addjunkie]

Connecting into a one pipe system the way you suggest simply will not work, needs a proper flow and return to the blending valve. Connecting upstairs and down will have an affect on the flow

This really is a time to do it properly

If he has access to up stairs for the return, could the supply be from upstairs loop too to a blending set up

 

[JimmyS]

You would be best fitting a small ufh manifold with a mixing valve and pump. You would be blending the cooler water returning from the ufh with the flow the remaining return water would be introduced downstream of the hot take off It will dilute the flow temp obviously which may have some impact on downstream rads. I don't see why you'd need a buffer but may be missing something. If worried about pump interaction put in a header a pipe size up.

 

[Kayos]

If he has access to up stairs for the return, could the supply be from upstairs loop too to a blending set up

Crossing 2 one pipe systems will cause problems throughout the house, I have seen it done and been the one who had to sort it

 

[Onoff]

Thanks all. The downstairs bathroom, on the CAD plan above, is the only room I've refurbished, "properly". There's 175mm of insulation under the floor, then the walls and ceiling are insulated too.

This is the stairs room, like a hoarder's paradise!

https://flic.kr/p/2fujCkX

You at least then step into this. I did the lot myself, back to bare walls and ceiling joists and the floor dug down about 18":

https://flic.kr/p/2g7vP3q

My idea was to get a nice bathroom done, with all mod cons, where you could relax and clean up after a days graft on the rest of the house. The next step required (in my grand plan) is to dig the floor of the stairs room up, build back up fully insulated and site the UFH manifold under the stairs so as central to the house. Then, as rooms get refurbished, do a UFH loop and connect up.

So as it stands I've the UFH / towel rad pipes exiting the bathroom where they sit, unconnected under boxes of her tat. She won't even clear the room so I can dig it up, literally " Where are we going to put it?" then goes off on one.

https://flic.kr/p/2pbiy3B

(Build a decent garden room for temporary storage or refurb the old stable block were other suggestions of mine...never mind).

SWMBO is really strangely resistive to me digging the floor up. All I ever get is " "You'll take too long!" She's been coming out with this for a few years now. Mental tbh (& menopausal). By not doing it we basically have an unusable bathroom in the depths of winter as there's no heating. That and I've a jobless 24 year old sat on his backside. He could be doing this whilst I'm at work. Proper mummy's boy!

So if anyone wonders why I escape to the pub when I can...

 

[Onoff]

That's me on the right btw:

 

[addjunkie]

Put wife and jobless son in an old static caravan in the garden…..then crack on at your leisure!

 

[minimutly]

Thanks all. The downstairs bathroom, on the CAD plan above, is the only room I've refurbished, "properly". There's 175mm of insulation under the floor, then the walls and ceiling are insulated too.

This is the stairs room, like a hoarder's paradise!

https://flic.kr/p/2fujCkX

You at least then step into this. I did the lot myself, back to bare walls and ceiling joists and the floor dug down about 18":

https://flic.kr/p/2g7vP3q

My idea was to get a nice bathroom done, with all mod cons, where you could relax and clean up after a days graft on the rest of the house. The next step required (in my grand plan) is to dig the floor of the stairs room up, build back up fully insulated and site the UFH manifold under the stairs so as central to the house. Then, as rooms get refurbished, do a UFH loop and connect up.

So as it stands I've the UFH / towel rad pipes exiting the bathroom where they sit, unconnected under boxes of her tat. She won't even clear the room so I can dig it up, literally " Where are we going to put it?" then goes off on one.

https://flic.kr/p/2pbiy3B

(Build a decent garden room for temporary storage or refurb the old stable block were other suggestions of mine...never mind).

SWMBO is really strangely resistive to me digging the floor up. All I ever get is " "You'll take too long!" She's been coming out with this for a few years now. Mental tbh (& menopausal). By not doing it we basically have an unusable bathroom in the depths of winter as there's no heating. That and I've a jobless 24 year old sat on his backside. He could be doing this whilst I'm at work. Proper mummy's boy!

So if anyone wonders why I escape to the pub when I can...

Get a skip...

 

[Stuartg1]

Repipe the lot, your wasting time and money trying to cobble it together. Like kayos I've had to sort out this sort of homebrew catastrophe..... Single pipe will not do what you want..

 

[addjunkie]

Get a skip...

Its actually quite therapeutic once you start…..

Big house refurbishment room by room is never going to be easy. We did 14 months in a static caravan to avoid it!

 

[Blobber]

That's me on the right btw:

View attachment 422511

Shes got you dressed quite well, not my style though!

 

[dobbslc]

No underfloor heating in my place but I am completely replacing a single pipe system that was just...
I only have the hall, ensuite and small office to do when the next phase of the refurbishment kicks off soon
I used two Emmeti manifolds in the hall cupboards and coils of plastic coated 15mm copper to the rads, the handy thing with doing it this way is you can just add the next room when you want to without any fuss.

 

[Onoff]

The fun of working on an old place! You have previous DIY disasters to deal with:

https://flic.kr/p/Qgjzvb

I went to reroute the single pipe up the hall, easy I thought, it's a suspended floor...

https://flic.kr/p/voyVhb

Then I found an old hearth I had to kango out.

 

[Onoff]

Its actually quite therapeutic once you start…..

Big house refurbishment room by room is never going to be easy. We did 14 months in a static caravan to avoid it!

My idea was...

Redo the downstairs bedroom first as a temporary lounge. That and the hall are all the original suspended floor. At the same time make the corridor to the little WC into an ensuite WC / shower. Would mean moving a stud wall. Thereafter it'd make a great kid's lounge and later on a downstairs bedroom for us.

What happened? She paid lip service to redecorating it, nothing structural and now it's the cat's room.

 

[dobbslc]

I see what the problem is here and it's not the house...

 

[dyno-tron]

Thought I’d show a pic of our UFH manifold which supplies our kitchen, maybe it will help with working out what direction to take with your system.

The rest of our system is conventional two zones (upstairs & downstairs) on separate thermostats and zone valves.

Kitchen UFH was added later and it behaves just like another CH zone because it has its own thermostat and zone valve, and the manifold takes care of its own temperature & flow circulation. It was an easy retrofit :-)