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Thread: Electric underfloor heating

  1. #1
    Automated Home Sr Member
    Join Date
    Oct 2009
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    65

    Default Electric underfloor heating

    I am grappling with electric UFH control at the moment. Appreciate thoughts on how best to set up. I have QRH relays controlling power to my electric UFH units which have their own thermostat and controller for programming (more for safety and not to let the pads overheat). The UFH is only really for comfort, as the radiators provide the main heating. I have set up HVAC for various rooms with different usage profiles, and they all seem to work fine.

    Getting the UFH integrated is a pain, though. I have set them up as "heating elements", which means that I cannot use them as a heat zone for a HVAC. Is it better to set up as a "boiler" and then have a separate HVAC? Essentially I have 3 UFH "zones" - the kitchen/diner, en-suite and main bathrooms. The kitchen/diner has a HVAC already, controlling the central heating boiler.

    I have set the en-suite and bathroom to "pulse on" (half hour) via QBIs so that I can turn them on before an evening shower and this aspect works fine. For the kitchen/diner, I would like the UFH to come on only when the kitchen/diner is occupied, except first thing in the morning, so that the floor is warm before we come down. The en-suite and main bathrooms do not have temperature sensors, and once again, I would like them to come on about an hour before we wake up to warm up the bathroom floors. I have set-up scheduled events to turn on and off in the mornings, but cannot quite figure out the best way to ensure that the kitchen/diner UFH is only only when it is occupied. Furthermore, I am a little concerned that the scheduled events will turn on the UFHs in the mornings even when we are away on holiday. Hence, my confusion! I thought that perhaps HVACs for the UFHs might be better, but I don't think I can get the profiles to just on and off without having the room temperature?

    To complicate things a bit more, I also have electric elements for the bathroom towel rail/radiators controlled via QRH which I would like to turn on for a short period in the mornings to warm up towels in summer when the central heating is off. Not sure how to do that (yet) ! Thought of using the scheduled events, but I don't think I can have multiple logic, ie House occupied AND Boiler off THEN pulse on towel radiators. The General Logic module does not seem to be able to check the state of the boiler.

  2. #2
    Automated Home Ninja Viv's Avatar
    Join Date
    Dec 2004
    Posts
    284

    Default

    Suggestions...
    Use a relay as a heating zone valve.
    Use an additional HVAC for each UFH zone.
    Use the outside temperature sensor (assuming you have one) as the HVAC room sensor. If not a sensor from some other part of the house say the hall.
    Use the room(s) the HVAC is controling as the HVAC presence input.
    Use the temperature profiles to control the heating on/off. Set the UNOCCUPIED profile to a very low value so heating does NOT come on at all with this profile.
    Set the OCCUPIED profile to say 0C when you do not want it on. Set it to 25C or higher when you do. Set it even before the room is expected to be occupied before you get up.
    Add the bedroom you occupy before going to en-suite (example) into the HVAC occupied profile or the HOUSE.
    Set Presence run on period to small period.

    All this should.
    Turn electric UFH on provided the Bedroom, or house or zone room is occupied at required time of day.
    Not turn it on if unoccupied.
    Heat the floor typically regardless of it temperature. Unless it is very warm outside when perhaps you do not want it on then anyway.

    Viv.

  3. #3
    Automated Home Sr Member
    Join Date
    Oct 2009
    Posts
    65

    Default

    Thanks. That makes sense! Trying it now.

  4. #4
    Automated Home Sr Member
    Join Date
    Oct 2009
    Posts
    65

    Default

    En-suite seems to be working OK. Shall try the kitchen-diner next....

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