Under-Floor Heating temperatures (and Karndean)

Hi folks - a bit of advice needed...
I have fitted UFH (Eco-Hometec) to our new kitchen/utility room and I'm gradually ramping up the temperature now (so as not to damage the screed). The (very poor) instructions from Eco-Hometec suggest the water inlet tempertaure should be set to 55degC. Currently I'm at just over 40degC and the room is warming up nicely. I should say the floor is ~25degC with my calibrated palm.
Is there an accepted temperature these systems should be run at? Presumably there becomes a point at which the screed can be damaged through thermal expansion and contraction.
Is there an accepted limit on floor temperature? Obviously you don't want people hurting their feet first thing in the morning.
Finally, does anyone have any experience using Karndean vinyl flooring with UFH? http://www.karndean.com/home.asp Karndean say it's OK up to a floor temperature of 29degC, but won't say what happens above this. Also they have no U-value data they are willing to share which concerns me. The benefit is the slightly more forgiving surface (compared to porcelain tile) and the variety of finishes. Also although it's ~50 p/m, probably cheaper than floor tiles once fitted. (I'll get someone in to do the floor - newborn + 2 toddlers has severely limited my DIY time! I did install the UFH though, so I don't feel /too/ guilty!)
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Tournifreak wrote:

BS EN 1264-3; The floor surface temperature shouldn't be more than 9degC above room air temp, i.e., 29 degC in normally occupied rooms or 33degC in bathrooms with design air temp of 24 degC. The floor surface temp in peripheral areas with higher heat losses can be up to 15 degC above room air temp. Some floor coverings won't tolerate temperatures this high.
I don't know the temperature at which the screed could be damaged, the edge insulation should absorb some expansion. I heard of a tiled floor which became corrugated after an idiot set the mixing valve to 100% over a week-end. A manual-reset high-limit thermostat to shut down the pump sounds like a good idea to me.
This doesn't give a water flow temperature, but you could work it out from knowledge of the floor structure & coverings, or do it empirically by measurement.

The above are recommended maxima, the design should work at something below this. If you have weather compensation (motorized mixing valve & outdoor air temperature sensor) , the flow temperaure will be operating below the design maximum for much of the heating season.

Not me.

Their guarantee is void, so they won't care.

Odd. Look up a generic value for vinyl flooring.
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We were somewhere around Barstow, on the edge of the desert, when the drugs began to take hold. I remember "Tournifreak"

I've set them at 40degC max and never had any trouble.
--

Dave

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Grimly Curmudgeon wrote:

Thanks Dave and Aiden for your information.
So that it's recorded for ever in the annals of google history, I thought I'd doa quick review of the Eco-Hometec UFH system.
I first saw it on ebay but bought direct from eco-hometec. I bought a 2-"zone" system, but with no individual thermostats. i.e. maniford with two outlets/inlets, one Honeywell CM67 controller. 130m barrier pipe. Manual control mixer. Paid 501 total inc VAT & delivery
Plus points: Cheaper than I could get similar Speedfit system from a plumbers merchant (although I'm sure many could negiciate a better discount than I could!) Easy to lay pipe - pipe clips worked well with Celotex Reasonable quality (Italian?) valves and fittings
Minus points: Rubbbish instructions. Really poor. The instruction booklet seems to be common to all the UFH systems they sell so much of the information is irrelevant. There were all sorts of extra pages of information thrown in the box that weren't included in the booklet. Diagrams and photos were almost illegible, and I'm glad I'm confident with electrics or I'd have had no chance following their wiring diagram! Obviously not designed for the basic DIYer in mind, but then perhaps your average hang-around-Focus DIYer wouldn't be fitting UFH themselves anyway! Pipe is 16mm diameter and incompatible with anything else in the whole world, or at least with anything available in Ipswich plumbers merchants. This is a problem if you are 3m short of pipe, like I was! The pipe is v. cheap - so buy extra! No design supplied, so I had to work out pipe runs etc myself.
But hey, it works, and it's lovely!!!
Regards,
Jon.
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Hi folks - a bit of advice needed...
I have fitted UFH (Eco-Hometec) to our new kitchen/utility room and I'm gradually ramping up the temperature now (so as not to damage the screed). The (very poor) instructions from Eco-Hometec suggest the water inlet tempertaure should be set to 55degC. Currently I'm at just over 40degC and the room is warming up nicely. I should say the floor is ~25degC with my calibrated palm.
Is there an accepted temperature these systems should be run at? Presumably there becomes a point at which the screed can be damaged through thermal expansion and contraction.
Is there an accepted limit on floor temperature? Obviously you don't want people hurting their feet first thing in the morning. <<<<<
Use an outside weather compensator for economy and confort conditions and a floor temperature sensor so the floor does not get too hot.
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