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Ecobee smart learning directly controling the boiler?

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JaymeHart
JaymeHart Member Posts: 71
in Strictly Steam

I have my Ecobee currently wired directly to my boiler (Rh and W) to TT from the boiler, with a separate 24V transformer feeding Rc and C for power.

I also have a Taco SR501 relay, which coild also power the thermostat via the typical Rc,W, and C connection.

I had previously wired it thru the Taco, but I needed an extra 24V transformer anyway to power a digital aquastat, so trying the Ecobee wired direct to the boiler TT with no relay in-between.

Amy I crazy? Is there a difference in how the Ecobee learns between these two options? With the Taco relay of course, the Ecobee would not have any additional input. When it is calling for heat, thats it, time to satisfy is the only external input.

Wired direct, is the Ecobee seeing the boiler response, including cutout due to pressuretrol/vaporstat breaks, etc? If so, that would clearly be the better way to provide data back to the thermostat to provide insight on how to avoid short cycles, etc.

Comments

  • pecmsg
    pecmsg Member Posts: 7,006

    what is there to learn?

  • JaymeHart
    JaymeHart Member Posts: 71

    that is sort of what I am asking. is there anything to learn about timing to avoid cycling?

  • Big Ed_4
    Big Ed_4 Member Posts: 3,495

    What are you controlling with the Bee …

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  • JaymeHart
    JaymeHart Member Posts: 71

    Single pipe steam boiler for a single family house, 2 stories + basement.

  • jesmed1
    jesmed1 Member Posts: 1,420
    edited February 7

    There's no difference. Either way, the Ecobee doesn't "learn" anything through the wiring. The wiring simply tells the boiler (or zone control) when to start running and when to stop running.

    The Ecobee "learns" only by sensing local room temperature where it's located, and by wireless temperature inputs from any remote sensor(s) you've paired it with. So for any given combination of settings (see below), the Ecobee learns how long a boiler run time is required to reach the setpoint. It gets quite accurate after a surprisingly small number of runs, so it "learns" very quickly, even after you change settings.

    Our Ecobees are wired direct to our two hot water boilers, and one way I minimize short cycling is to adjust the "differential" setting in the Ecobees. If my memory is correct, you can choose differentials of 0.5, 1.0, 1.5, and 2.0 degrees. Our hot water boilers work best with differentials of 1.0 or 1.5, which result in typical run times of 30-45 minutes, followed by 2-4 hours of idle time.

    The other way to minimize short cycling is to specify a minimum run time. I think the highest number you can set for a minimum run time is 20 minutes, so that's what I've set ours for, but because it always takes longer for the boiler to heat the large volume of water in our radiator system, our run times are never less than 30 minutes. So in our case, the minimum run time setting doesn't ever matter.

    With a steam system, you'll have to find the settings that work best for you. By adjusting the differential and the minimum run time, you'll find the right balance to avoid short cycling.

  • JaymeHart
    JaymeHart Member Posts: 71

    thanks Jesmed1. that is what I figured, it was outcome based on those parameters only, and not learning anything from the RW/TT connections.

    I am putting the Taco relay back, simply becuase thst way I get the nice little LED signal on whether the thermo is calling for hest or not.

  • jesmed1
    jesmed1 Member Posts: 1,420

    That will work fine. And there are many other steam users who have Ecobees that work well with their boilers, so there will be no shortage of Ecobee + steam discussion threads on the Internet with advice on differential settings, etc.

  • Big Ed_4
    Big Ed_4 Member Posts: 3,495

    Best to interface the Bee to a steam boiler with the 501… Power the 501 and use the t1 t2 and C to wire the bee …Use the dry contact end switch in the 501 to jump out TT on the boiler …

    Steam heat cycle is 3 per hour..

    I would stay away from twining transformers with Smart thermostats ..Best to keep it clean ..

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