Underfloor heating temporary use.

[zippyelise]

Hi,

I've installed piped underfloor heating in my kitchen extension and it will be eventually be connected to a manifold in the old kitchen that will become a utility room and a bathroom.

I won't be doing these until the new year so the floor remains unused. In the old kitchen is a radiator that is now not needed.

What I was wondering is whether I could connect the underfloor heating to the radiator pipework as part of the heating network in the interim. I know heated floors need to be run on their own supply and with their own timing but it would be better than nothing?

Will the central heating pump be able to cope with the load or can the floor only be run by a seperate pump? There will be no other radiator on the loop.

The boiler is only running a small house, four other average sized radiators to be precise. If the pump burns out, I do have a spare knocking about!

Thanks in advance

 

[Bahco]

Your kitchen would be hotter than a cannibis factoryif you connect it up. Don't think it will do your floors or your CH much good either.

See what the other guys think but I would not attempt this.

 

[zippyelise]

Your kitchen would be hotter than a cannibis factoryif you connect it up. Don't think it will do your floors or your CH much good either.

See what the other guys think but I would not attempt this.

Why would it be so much hotter doing it this way? Underfloor heating uses the same water as the central heating when installed with a manifold, it just uses a seperate thermostat and timer as the performance is different. I'd be using the thermostat on the radiator which should shut the flow much like a TRV when the room's hot enough, so it will act like a big radiator (just like a heated floor should!) surely?

 

[fazedup71]

wrong, under floor heating uses a mixing valve and normally a separate pump, it does not run at the same temp as the rest of your system! burnt feet is your future!!! don't know how the small single room kits work, but you cannot just connect it up

 

[looneyfitter]

the underfloor heating could be connected upto the existing circs and should be fine upto a max of 15m 2. The problem you have is that your central heating runs at 80-85 deg where as UFH should run at no more than 50deg c

Be careful running hight temps through your UFH if it is in screed/concrete

You could always lower your boiler stat down but this will then have an effect on the radiator ouput.

 

[zippyelise]

the underfloor heating could be connected upto the existing circs and should be fine upto a max of 15m 2. The problem you have is that your central heating runs at 80-85 deg where as UFH should run at no more than 50deg c

Be careful running hight temps through your UFH if it is in screed/concrete

You could always lower your boiler stat down but this will then have an effect on the radiator ouput.

Interesting, thanks. It is in the screed and the floor area is just under 15m 2 as it happens.

I do run the stat quite low, about 60deg c, as the radiators were overspecced for the house so it gets very hot if it's up high. I'll lower it and give it a go and see if it works. If it doesn't, I can just chuck an electric heater in there for the winter months!

 

[Norcon]

the underfloor heating could be connected upto the existing circs and should be fine upto a max of 15m 2.

No it will not. Not without a valve fitted.

 

[zippyelise]

wrong, under floor heating uses a mixing valve and normally a separate pump, it does not run at the same temp as the rest of your system! burnt feet is your future!!! don't know how the small single room kits work, but you cannot just connect it up

Sorry, I missed this reply

That's very useful information, I didn't know that it used a mixing valve though it is a single room system so I'll have a peruse of the instructions and see what I can find.

Cheers all

 

[Bahco]

Just leave it be!

 

[Norcon]

Danfoss make a valve suitable for a domestic application like this.
A FHV-R (return temperature limiter).
BES supply them for about forty quid. Suitable for 15 sq meters.
A "double meander" (rehau spec) or counter flow pattern is recommended for their use.

 

[fazedup71]

you can buy single room systems that does not use a mixing valve as such but use a return limiting valve, not sure how well they work, having never fitted one myself

 

[zippyelise]

Danfoss make a valve suitable for a domestic application like this.
A FHV-R (return temperature limiter).
BES supply them for about forty quid. Suitable for 15 sq meters.
A "double meander" (rehau spec) or counter flow pattern is recommended for their use.

Those valves look just the ticket, in fact after reading about them I'm starting to think it will be a neater solution that a manifold seeing as it's just for one room. I have an appropriate pattern too and £40 isn't much to experiment.

Thanks for that

 

[looneyfitter]

You said you wanted to use it TEMPORARY so YES you could just connect it up. This is why i said you MUST LOWER your boiler stat. The floor screed must not come into contact with water any higher than 50 deg c.

Ideally a blender, manifold, pump, high limit stat and room stat should be used together to create optimium conditions.

Why is it that some engineers jump in feet 1st without reading what was asked in the 1st place.

READ what i said norcon !!!