Easiest way to connect up new ufh loop.

[Deluks]

I have laid some pex in concrete, only about 3sqm in total, and left the ends in a small cupboard which houses 15mm copper CH pipes (the flow and return for a radiator in an adjoining room)

Thinking of ways to connect up the loop, would a pair of these be worthwhile?

2 port manifold

Connect one to the flow, one to the return, connect the ends of the pex to one of each. Use the valves to control the amount of hot water passing through the loop (and to isolate if necessary)

I'll blank off the second port, and keep it as a spare for any future addition.

1) Does my plan make sense?

2) Would I need to have valves on both flow and return, or just one. (ie: could I buy one valved and one non valved manifold?)

3) No control for the heat in the ufh but only a small area so I'm not too bothered, and could always add control at later date on the plastic side of the system, right?

 

[bookahandyman]

from what i see you will need two of these, one for flow and one for return. as for seperate control i would advise putting in now as the warm up time for the floor against the rads is longer and once your heating in the rads is satisfied the boiler will cut off well before your floor even starts to feel warm.

i did a job for a kitchen company taht fitted a danfoss underflor thermostatic blending valve like this.. http://danfoss-randall.co.uk/xxTypex/207541_MNU17479715_SIT313.html it basically created an underfloor radiator but had the problem that the house heating was only on for a few hrs a day and the floor never warmed up.

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[bengasman]

And how are you going to connect your mixer, your second pump, and your secondary controls?

 

[Deluks]

And how are you going to connect your mixer, your second pump, and your secondary controls?

As I mentioned in Q3, none.
But would it be possible to add them late? after the valve on the manifold?

The room in question is the kitchen and doesn't need 'proper' heating, just looking to take the chill off the floor. All insulated below n suchlike so it hasn't got a lot of work to do.

 

[bookahandyman]

do it properly with a manifold / pump and zone valve , seperately controlled, or you are wasting your time and money.

 

[bengasman]

And how are you going to connect your mixer, your second pump, and your secondary controls?

As I mentioned in Q3, none.
But would it be possible to add them late? after the valve on the manifold?

Missed that one.
The answer is:
No, you can not do it this way. No, you can not add it later.

 

[Deluks]

do it properly with a manifold / pump and zone valve , seperately controlled, or you are wasting your time and money.

I don't see this as such a futile exercise.

As I understand UFH. A hot water pipe passes through concrete, transfers some of that heat into the concrete, making the concrete warmer in the process. (Granted, exactly how warm is yet to be observed)

Bengas: By adding the manifold, am I not creating an 'isolatable' branch from a hot pipe. So how would it not be possible in the future to isolate/disconnect and reconfigure where/what that hot water is doing?

 

[bookahandyman]

do it your way then.

 

[Deluks]

do it your way then.

I'm not doubting your advice (which I am grateful for) or knowledge.
I just like to understand the ins & outs when I'm wrong, and at the moment I don't.

*edit* forgot to ask, what area was the UFH in the kitchen job you mentioned?

 

[bookahandyman]

the job that diddnt heat up was about 6 sq mts. with celotex insulation and heat shield plates between joists and still wouldnt warm up.

In my own house i put in two loop sytem in screed covering 15 sqmts and had it controlled seperatley with double s plan. and two port manifold and pump. the house heating would come on at 6.30 am and the floor at 4am.
you will be suprised how long it takes to warm the concrete before any heat comes through the floor. i used to have it on /off every other hour during the day just to keep it luke warm. and that was in a new extension with full insulation in wealls floor and roof.

 

[bengasman]

Bengas: By adding the manifold, am I not creating an 'isolatable' branch from a hot pipe. So how would it not be possible in the future to isolate/disconnect and reconfigure where/what that hot water is doing?

Because ufh is a totall different kettle of fish working in completely different way at different times and different temperatures. So, no, you are not just creating an isolatable branch.

 

[Deluks]

Bengas: By adding the manifold, am I not creating an 'isolatable' branch from a hot pipe. So how would it not be possible in the future to isolate/disconnect and reconfigure where/what that hot water is doing?

Because ufh is a totall different kettle of fish working in completely different way at different times and different temperatures. So, no, you are not just creating an isolatable branch.

So typically, it would need it's own feed from the cylinder/boiler, seperate from the rad circuit??

 

[bookahandyman]

you can take the flow from the rad circuit but it has to be connected and zone valved before it gets to the first radiator on the exisiting heating. The return can join anywhere in the return pipework.

 

[Deluks]

you can take the flow from the rad circuit but it has to be connected and zone valved before it gets to the first radiator on the exisiting heating. The return can join anywhere in the return pipework.

I believe this to be between the first and second rads (bathroom and living room) or poss second and third (bedroom and living room) It would be possible to pipe up through the cupboard and back to the start of the rad circuit. That would be a 'bathroom floor up' job. Which is another job for another day (I can't be arsed)

The 2nd system layout diagram from the link you provided looks like what I'll be attempting, although the flow would be tee'd off and not flowing exclusively through the floor. By the sounds of it the circuit will work the same as a rad in design, with the Danfoss gubbins acting like a TRV.


It's only 3sqm, I'll take a punt.

 

[bookahandyman]

if you use the danfoss it will be in effect another rad. and wont warm the floor let alone the room unless your heating is going to be on for over four or five hours at a time.if you have TRV;s on your rads it may help but i dont think you will be a happy bunny.
Good luck , prove me wrong and let me know what results you get.