13 Feb 2005
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United Kingdom

Due to a change last minute change of flooring from wood to tiles we would like to install wet underfloor heating in a new extension. I have seen a kit that cover 24m2 which would seems ideal. http://www.floorheatingonline.com/s..._water_underfloor_heating_extension_pack.html

I have a block and beam floor that is going to be covered with 100mm celotex insulation and then screed. To install the heating pipework is it just a matter of stapling the pipework over the celotex and then screeding in concrete. All of the connections to the existing heating system will be made by a heating engineer but i would like to lay all the pipework myself to save on cost.
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No its very easy!

More problematic is to understand and come to terms with the operational aspects and disadvantages of UFH and to calculate the likely heat output.

I am suspicious of the output they claim! It all depends on the type of tiles used and I would suggest 50-60 watts/m² would be much more realistic.

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Thanks for the reply. I'm not too worried about the heat output that much as there are also going to be normal radiators in the room. My main aim is to give some warmth to the tiles underfoot. I did consider electric underfloor heating but the installation cost is similar yet much more expensive to run.

Back to my original question though, is it just a matter of stapling the pipework to the celotex and then getting the builder to screed over the pipework?
Reading up on it it does look like its a matter of stapling the pipework to the insulation.

I have a bit more of a technical question now:

I have a Vaillant Ecotec plus 837 boiler. At present it is controlled with a Vaillant VRT360f wireless room stat. Reading the installation instructions on the heating pack it states there must be a switched live going from the underfloor timeswitch to the boiler to operate the boiler pump etc. At present terminal 3&4 are looped and the wireless controller connects to the 'e'bus system. Will it be possible to still utilise the programmable room thermostat and use the UFH timeswitch as per the instructions.

Thanks for any advice
Hi, did you get any reply about this? I am in the same situation at the moment.

I have a Vaillant 837 and a VRT360, would I need to disconnect that in order for the UFH to work, also have a thermostat fitted in each room upstairs, would the boiler heating system only work of the temperature that the VRT360 senses?

you will have to ditch the 360 I am afraid, it works on an e bus system, if the stats you have up stairs also work on the e bus, you will have to change these as well, the 240v connection (3, 4 and 5 on your boiler) can be used with an s plan to control your radiators and your ufh.
Vaillant have launched a multizone compatible e bus system. I haven't seen it working and I know they had a false start with it about 18 months ago and were backpedalling.

It is one of the things I want to ask my local area rep, when one stays in the job long enough. Vaillant UK seem to suffer from rather poor morale, as far as I can see.
their new system might be multizone/e bus compatable but its not compatable with their combi boilers, something to do with the different software .
Absolutely, I should have read the question better. I'll get my coat.

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