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Thermostat for new high efficiency boiler with ODR

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scv900
scv900 Member Posts: 10
in Domestic Hot Water

Are there thermostats that work with a high efficiency boiler with ODR and can override the ODR when the difference in temperature at the thermostat and the set temp is really high?

We re-did the basement and they poured a new slab with hydronic heat in it. We will use a new high efficiency boiler with an indirect hot water tank to heat the floor (and another pre existing radiant floor in the house). The plumber said he'll setup the ODR on the boiler.

As I understand it, this means it'll take a similar amount of time to heat no matter the outdoor temp, and the water that is circulated will be warmer the colder it is outside.

The use case I'm wondering about is if we've left the house for the weekend and set the temp to say 55, and want to quickly heat the room to 70 on a cool (40F) day when the ODR would normally be keeping the circulating temperature lower, is there a thermostat or systems that can override the ODR and call for warmer circulating water in this case (eg when the set vs actual indoor temp delta is >8F) and we want to heat faster than normal?

I've looked around here and online and can't find the answer to this question, and my guess is because I'm using the wrong terms.

Comments

  • Big Ed_4
    Big Ed_4 Member Posts: 3,440

    Not sure what boiler are you using , you would want to add their room sensor for some control …

    There was an error rendering this rich post.

  • Jamie Hall
    Jamie Hall Member Posts: 27,086

    Not sure about the overall plan here. As I am sure you are aware, in-floor radiant heat is inherently slow to change temperature. Changing the temperature by 15 degrees F is going to take a while — likely a day or so — even at maximum safe floor temperature.

    Many, if not all, mod/cons with ODR have a "boost" function built in which will raise the setpoint under certain conditions. That is probably your best bet.

    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • GGross
    GGross Member Posts: 1,808
    edited February 5

    Just read that you have infloor heat, boosting the temp for in floor can be tricky, its do-able but you run the risk of floor damage. Either way the floor will take a long time to heat back up. Honestly If I was leaving for the weekend I would say its not worth it at all to turn the heat down on a radiant floor. I would need to be leaving for over a week personally, and then I would still just turn the temp up on a wifi stat about 2 days before I come home. There is no "quickly raise the temperature" or lower the temperature, with most radiant floors, and the ones I am familiar with that are quicker response all use high temp anyway

    Leaving the rest of what I wrote here for reference in case it helps someone

    You would need a communicating system. thermostats, at least typical variety, do not communicate with your appliance, they are a switch.

    Most condensing boilers have some type of ramp delay/boost feature, or a wifi connection that would allow you to boost the heating curve right from your smart phone. ramp delay would increase temperature if the call for heat last a certain amount of time

    The other option would be to abandon the internal boiler ODR, use a third party controller with a communicating thermostat (indoor reset) and you would need to control the boiler temp either through a 0-10v signal if it accepts one, or a mixing valve. the mixing valve would lower your efficiency as the boiler would always fire at a higher temp

    Some boilers offer a room feedback sensor that provides indoor reset technology to work in tandem with outdoor reset technology (NTI is one, at least the newer models)

    I personally recommend for the easiest path of least resistance, either a wifi stat which you turn up before coming home. A boiler app if yours offer one so you can control the curve from your phone when you get home. Or what I do which is to make about 5 button presses on my boiler to turn the curve up, and then turn it back down the next day.

    bjohnhy
  • HydronicMike
    HydronicMike Member Posts: 306

    Many of the Tekmar thermostats have an 'away' feature that will lower temps. But like the others said, recovery may be very slow.

  • pedmec
    pedmec Member Posts: 1,293

    Is all the heating done by the radiant flooring? any other type of emitters?

    GGross
  • kcopp
    kcopp Member Posts: 4,647

    Just set it at the desired temp and walk away…

    Let the boiler control do its thing.

    Dont use a set back ..period.

    I do this in my own home. Set at 67* in Oct and then dont touch it until May.

  • pecmsg
    pecmsg Member Posts: 6,953

    with radiant you have little if any control!

    Set it and forget it!

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