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Help with rinnai i120sn outdoor reset

Hey everyone, ive been using this site for info but this is my first time posting.
 I have installed Hydronic staple up heat in my 1980's log home in Ontario Canada. I just hooked up the new Rinnai i120sn heat only boiler this week. Ive been trying to figure out all the settings mostly just the outdoor reset. I have the tekmar sensor installed to the boiler. From the boiler i have wired a caleffi switching relay that powers my 2 zone pumps, each zone has a thermostat. first floor zone has 4- 300' 1/2" pex loops stapled up with heat transfer plates. 2nd floor has 3- 300' 1/2" pex loops with heat transfer plates. 

I have the boiler programed for outdoor reset and set to staple up mode, but it seems the pumps only run when the thermostats call for heat. ideally id like zone pumps running constantly with the boiler changing water supply temps dependant on the outdoor temperature? Am i getting this right? Any help would be much appreciated.


  • Zman
    Zman Member Posts: 7,572
    I am not familiar with the controls on that model.
    Are you able to see the outdoor temp and corresponding boiler target temp on the control screen?
    If you get the outdoor reset dialed in perfectly, you should (theoretically) be able to set the t-stats a little higher than the temp you desire and let it run as you describe.
    My guess is this will be challenging in a log home retro. The system would have to be perfectly designed and balanced. Variable factors like solar gain and air infiltration are hard to mitigate, especially in a log home.
    "If you can't explain it simply, you don't understand it well enough"
    Albert Einstein
  • neilc
    neilc Member Posts: 2,707
    sounds like your thermostats are shutting off at temp, confirm ?
    is house comfortable now?

    post your manual PDF,

    what is your design temp there? -10F ?
    how well are you air sealed, and insulated?

    my seat of the pants say,
    set your OA reset to as low as possible and still maintain comfortable home,

    assuming ~ 30F OA temp,
    -10 OA = 110 high supply temp,
    50 OA = 80 low supply temp,

    again, assuming ~ 30F OA temp,
    if house is maintaining, and cycling on the thermostats,
    every 3 days(settling time), lower both supply temps 5*, until the house starts getting chilly,
    then come back up 2, 3, or 5, and stop,
    if the house is NOT keeping temp, add 5 ~ 10 to both supply temps,
    then go back and try backing down 2, every 3 days(settling time),

    if house is "uncomfortable" at OA temp extremes,
    only change that corresponding supply temp,
    if you're cold at -10, add the 5~10, to the high supply temp setting

    this can take a while, possibly the rest of the season to get it fine tuned,
    at some point you won't much need the thermostats, at least not both,
    this will matter on how well the 2 zones are engineered, and balanced.
    known to beat dead horses