Wet ufh issues. Any advice?

[Dirty tree]

Hi,
our plumbers installed a john guest water underfloor heating system in our kitchen extension.
The pipes were laid and slab poured and all was good.It was connected up correctly to the manifold and is powered by a worcester Greenstar 37kw boiler which is overkill for our small house.Everything is working fine except......
We now have one area of hot floor and large areas of cold or luke warm floor. Approximately half the tiled floor is cold and return pipe going to manifold is luke warm at very best.It has been flushed through and there are no air blocks or blockages at all.
The floor space of entire kitchen is 32m2 but actual floor space for UFH is around 25m2.
Our plumbers tell us that this is how UFH systems work and that the entire slab/floor does not have to be uniformly heated and that cold patches are normal. It is our suspicion that they should have installed a dual system so that each pipe run had half the kitchen floor to heat and thus eliminating the cold areas and making the system more efficient.
The pipe was also run in one direction so to speak without the flow and return being always side by side.
The UFH system actually does heat up the room but it is annoying that half the kitchen still has a cold floor to touch and i can't help but think that the whole system would heat quicker and be more efficient if the whole slab was warm and not only 50% of it.
Your thoughts please and any advice.
Is this normal?
Should the entire slab be warm or are cold areas acceptable?
Is our system in some way worse off for the way it has been installed?
Is there a widely accepted correct/standard way of laying pipes so that the entire slab warms up evenly?
Should we have had a dual two pipe system for our floor space of 25m2?

looking forward to some advice.

thanks.

 

[Dotty]

UFH is only one loop of pipe laid down in a particular pattern according to a design usually supplied by the manufacturer as a free service.

The temperature should be fairly uniform across the screed.

Sounds to me like they've made an expensive cock up but one of the lads more conversant with UFH will be along shortly to confirm this or give me a slap....

 

[Destroyer2813]

I don't use jg put polyplumb and for that size area you would be using a three port manifol, so you have 3 separate loops to heat your floor space. From what you are describing sounds as if they may have just gone in one side of the room and out the other did you take any pictures?

 

[Chalked]

How many loop in the floor?
it will be either air locked, not balanced, kinked, or too long?

 

[Dirty tree]

I don't use jg put polyplumb and for that size area you would be using a three port manifol, so you have 3 separate loops to heat your floor space. From what you are describing sounds as if they may have just gone in one side of the room and out the other did you take any pictures?

Thanks for your opinion.

yes i do have photos.
they went onto the floor with the pipe from the manifold, snaked all around the room and then came back to the manifold.
Have i been left with a bad ufh system then?

anymore opinions gladly welcomed.

 

[SimonG]

There are maximum loop lengths to prevent this sort of thing happening. Any pictures of the manifold and controls arrangement?

Was the pipe under pressure when the screed was laid?

 

[Neil K]

Might be something as simple as flow and returns mixed up at manifold aswell. If that's all it is then it's not too bad

 

[Dirty tree]

Might be something as simple as flow and returns mixed up at manifold aswell. If that's all it is then it's not too bad

Hi guys,
everything is connected perfectly and everything is working as it should.
there are no blocks or kinks in pipe.
i would like your opinions regarding size of room and length of pipe used.
they used one pipe on 25m2 of floor.
is this why the floor is hot where the pipe comes onto the floor from the manifold but by the time it has reached the second half of our kitchen floor which is further away from the manifold the water had cooled down and the slab is cold.
will our system work properly if only half the slab heats up?

thanks

 

[Neil K]

How many loops is there?

 

[Neil K]

A photo of the manifold would help

 

[Dirty tree]

Only one loop.
spaced at around 100 mm apart laid in serpentine fashion and around 220 metres long.

 

[Dirty tree]

We have 220 metres of one single pipe at 100-150 ish spacings in a serpentine layout.

 

[oz-plumber]

What diameter pipe did they use?

25 m2 could be pushing it on one circuit, but not overly.

What are the distances between the pipes?

Post a couple of pics.. it will be easier to see what has been done

 

[SimonG]

Far too long. Normally its 100 to 120 metres.

 

[kris]

Did you have a pump for the UFH at thye manifold or is it simply off the boiler, i know its only 1 room but better ,

 

[Chalked]

It's double the recommended length.
no wonder it's cold.

 

[SimonG]

Still need pictures.

Sounding more and more like something cobbled together.

 

[Chalked]

Just done a quick dork out o. My ufh app.
Recommends 3 loops, with a total length of 205m at an average of 159mm centres.

you will need massive water velocity to get any heat.

balls up by installer, the stupid thing is that splitting it up into 3 loops uses no more pipe.

 

[plumben]

Only one loop.
spaced at around 100 mm apart laid in serpentine fashion and around 220 metres long.

did your instller use a plan/specs form a manufacture or just make it up himself

 

[Ermintrude]

I would say it's the size of run . What insulation was under the slab?

You could fix it mechanically by installing a massive pump and blending valve set. Must have joined pipe or they spaced pipes too far apart. U could get it more uniform by running pump constantly even when rooms warm enough. - need extra controls but running the pumps would even out flow.


Really sorry to hear that this had happened. Were they the only quote u got? Really not done properly. Take them to the wall and have it all redone ?