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ufh and backboiler

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  • 16-08-2010 12:29pm
    #1
    selfbuildsoon
    Registered Users Posts: 53 ✭✭


    can ufh be ran off a backboiler like rads can?


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    #2
    AckwelFoley
    Registered Users Posts: 12,556 ✭✭✭✭AckwelFoley


    selfbuildsoon wrote: »
    can ufh be ran off a backboiler like rads can?

    In a word, no.

    The temp required for rads is alot higher than the temp used in UFH.

    UFH is designed to operate at around 30 degrees, As backboilers can heat up to well over twice that amount its not suitable for UFH, and unfortunatley there is no way (i know of) to regulate the heating out of a backboiler


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    #3
    Mike2006
    Registered Users Posts: 689 ✭✭✭Mike2006


    What you could do is drive a central heating coil in a cylinder with the back boiler and use the water in the cylinder to run your underfloor heating combined with a mixing valve from the return loop on the UFH.


    Mike


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    #4
    selfbuildsoon
    Registered Users Posts: 53 ✭✭selfbuildsoon


    so it can be done! will be very disappointed if i have to put rads in! btw does anyone know if the size of the backboiler should be the same size as if we were going with heating rads? so if we were using the back boiler for rads we'd need a huge one to heat around 18 rads, would be still need a huge one to heat the underfloor as it runs on a lower temp than rads, or could we go with one to heat 10 rads?i'm clueless so some help would be much appreciated


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    #5
    Mike2006
    Registered Users Posts: 689 ✭✭✭Mike2006


    It will depend on your square footage really and how much UFH pipe you will have.

    Each rad holds on average 6 litres of water so 18 rads would be 108 litres of 60 DegC water.

    Each 10 metres of UFH pipe holds approx 1 litre so this equates to about 1000m of pipe which at an approximation would cover about 1800 sq ft...

    But, that 108 litres of water would be reauired at about 38DegC instead of 60 DegC so you would actually need less that that for your UFH system...

    You really need to get it all calculated correctly based on house layout, size, insulation etc... as all that anyone here can provide you is a bit of guesswork... (I am open to correction here)

    Mike.


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    #6
    selfbuildsoon
    Registered Users Posts: 53 ✭✭selfbuildsoon


    Thanks Mike. The house is 3,500 sq.ft. Do you know where I could get this properly calculated?


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    #7
    Mike2006
    Registered Users Posts: 689 ✭✭✭Mike2006


    You are basically looking to size a boiler for your house.

    Heat Loss calculations will be the same regardless of whether it is UFH or radiators.

    Use this link to give you an estimate of your heating requirements. And if you just have a back boiler, then that is the size one that you need.


    http://www.idhee.org.uk/calculator.html


    (Use Northern Ireland as the location - Closest to home.)

    Mike.


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    #8
    selfbuildsoon
    Registered Users Posts: 53 ✭✭selfbuildsoon


    Thanks for that Mike, much appreciated.


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