"Alternative" UFH Installation

[FischerPrice]

Hi

I'm currently having some building work done which includes adding underfloor heating to a room in a house which already has radiators. The builder has installed his own "design" of system which I think is best described as not-fit-for-purpose. I asked him to remove it and install a proper single room system with a blend valve etc. but he is adamant that his installation is perfectly acceptable and is very upset that I've questioned his professionalism. Apparently he has one just like it in his own home.

Here is a diagram of what is installed together with a picture of the pump hanging from the flow pipe.

There is no bracket to fix the pump.

Has anyone ever seen an installation like this that worked?

Are there any official documents that describe how WET UFH should be installed?
(I mean professional association docs rather than manufacturers guides)

Any comments or thoughts on this would be very welcome.

 

[chrishutt]

As you say, not fit for purpose. The temperature that is suitable for UFH is lower than is normally used for radiator circuits, hence the use of blending valves, etc. There is a system available (marketed by Danfoss I think) for small area UFH installations where a blending valve is not required and the return temperature is thermostatically controlled instead.

Clearly your builder is not competent to be installing UFH, and perhaps not even heating systems in general. It might be a good laugh ... I mean worthwhile ... posting a few more pics of his heating work for us to pick holes in.

 

[simond]

The floor is going to get too hot.......

If it is a concrete screed it could crack.

Your problem is that there isn't really a generic guide to UFH, because each manufacturer has their own design guides.

My suggestion would be to say that since he has used John Guest Speedfit pipe, he is obliged to follow their recommendations for UFH. You will find their product guides on the JG Speedfit web site.

Other members of the public reading this should be reminded that builders are not usually heating technicians - allowing them to design systems can be a big mistake, even if it does appear convenient at the contract stage.

 

[Onetap]

The floor will probably get too hot; is 27 degC the recommended maximum.

The return from the UFH to the boiler will get to cold (if it's a non-condensing boiler) some of the time.

The return from the UFH to the boiler will be too hot most of the time and will lower the boiler's efficiency, especially if it's a condensing boiler.

Either he hasn't got a clue or he's trying to rip you off.

I'd bet the insulation in the floor is inadequate.

 

[FischerPrice]

Thanks for the comments, you've confirmed everything that I already thought but was starting to doubt. I'm very concerned about some of the other work that has been done so will be checking everything very throughly

I'm going to get the installation done properly with a Speedfit single room system.