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radiant adjustment

losthopelosthope Member Posts: 10
the first floor of my home is radiant that is controlled by an taco i valve. how do you guys setup water temp? do i set it up with the lowest possible water temperature that will still heat the house(longer circulation time)?... or do i turn the water temp up a little to shorten circulation/run time?


  • kpc_59kpc_59 Member Posts: 1
    the latter...

    get er done asap.
  • losthopelosthope Member Posts: 10

    so i will use less oil with hotter water temps?
  • losthopelosthope Member Posts: 10

    do i turn it up, as long as it doesnt heat the house past the thermostat set point?
  • Rich L.Rich L. Member Posts: 414
    Minimum temp to heat the space

    I disagree with KPC. I set up all my radiant jobs with the lowest possible water temps that will heat the space to the desired temperature. I ALWAYS recommend outdoor reset to automatically accomplish this.

    Radiant is not like forced air. You don't want to see temperature swings with the unit cycling on and off. The general philosophy with radiant that I use is lowest water temps that will allow the circ pumps to operate for the longest periods possible.

    Think of it this way. If you run higher water temps, you heat up the space and the floor cycles off. Now the floor cools off even though the space temp is ok. Now we have a cool floor and that generally is acompanied by an unhappy customer that thought this radiant stuff was always going to mean "toasty warm floors". It's the opposite of what you usually want.

    Lower water temps, longer cycle times, more comfortable floors.
  • Rich L.Rich L. Member Posts: 414
    Less oil

    You COULD wind up using less oil because you're not putting as much heat/ energy into the water to get the higher temps.
  • jp_2jp_2 Member Posts: 1,935
    maybe, maybe not

    depends on if your boiler is set up to be able to run the load for long periods without short cycling or cycling on high limit.
  • losthopelosthope Member Posts: 10

    ya the Ivalve i have has outdoor reset. and my aquastat has a high limit differential of 30 degrees so short cycling isnt a problem. any other thoughts?
  • kpc_62kpc_62 Member Posts: 1
    need more info.

    it need to heat the space in a reasonable amount of time... if it takes 6 hours to raise it 2 degrees that will not save you much. What are the numbers? what is the application? staple up ? slab? plates? no plates? are we talking 140 design temps or 90? I have used the I valve a number of times. it gives you a number of options and choses depending on the boiler and design....
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