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Triangle tube not \"Pumping Away\"

eluv8 Member Posts: 174
The reason for the confusion on the size of your boiler, is your on the edge of the boilers limits after deration,(Input Btu's is different than Output Btu's), depending on how much you trust the software and your calculations. Usually uponor ADS is padded pretty heavily so you would probably be fine with the tps60. What is the btu load of your smallest zone, can the tps110 modulate down that low, or will it cycle excessively during the shoulder seasons. May consider piping with a buffer tank. Best of all worlds but a little more expensive up front.


  • Craig Benson
    Craig Benson Member Posts: 15
    Triangle Tube Solo 110 not \"Pumping Away\"

    I have just finished reading Dan Holohans books regarding hydronic heating as well as Siegenthaler's text and am about to dive into a radiant heat system for my new home I am building. Construction details - ICF basement and 2x6 standard construction main floor w/ Warmboard radiant subfloor, 3474sf total heated space.

    I am leaning towards a Triangle Tube Solo 110 based on info here and recommends from established plumbers. This boiler comes with it's own circulator factory installed. In this case one would be forced to pump the primary loop towards the "Point of No Pressure Change". The secondary loops would "Pump Away" but not the primary. The closely spaced tees and common piping are also shown installed ahead of the expansion tank.

    Is this a real concern in a relatively small (4.5gpm+3.3ft head loss) system? I am using the Uponor ADS software for heat loss calcs and get a total heat load of 39,384BTU/hr. I will also be providing DHW with an 80-115 gallon indirect tank. This will add some to the total heat load but I am not sure how much. My fuel source is propane and I live at 6000' with a design temp of 0* and 15mph.

    Should I be considering a smaller boiler instead of the recommended 110? Another semi local installer suggested a 140K instead of the 110 for a faster DHW response. I suggested a bigger tank...

    Thanks for your time, any and all advice appreciated!
  • Josh_10
    Josh_10 Member Posts: 787

    Craig, a few of the rules have changed since Dans book was written. It is a very good book and helps you understand the fundamentals, however, there's a few more items that must be considered these days.

    Read the Idronics paper (available at the Caleffi website) on air and dirt seperation. It will build on everything you have learned in pumping away, and it will answer your questions. You will find TT is doing it right though.
  • Tony_42
    Tony_42 Member Posts: 37
    110's too big

    You should get the PS60 instead. Less short-cycling. 40 or 60 gallon IDHW or a 30 with a mixing valve.

    I installed a PS60 & a Smart 30 with a Smart Sensor programmed "tight" and have no problems. Customer has a teenager who takes 15 minute showers w/o running out.
  • Craig Benson
    Craig Benson Member Posts: 15

    Thanks for the replies. The Caleffi link was very helpful, never really studied air separators much but there is some good info there for sure.

    I am also leaning towards the TT Prestige 60 as well. I will do another heat loss to double check the software because the Warmboard kinda throws the calcs off a bit. That is another reason where I think I will actually need less heat. The 60 gallon tank would probably be fine, we have the typical huge master bathtub and double shower but a higher storage temperature would mitigate that easier than the huge storage tank.

    Thanks again - all input is appreciated!
  • Uni R_2
    Uni R_2 Member Posts: 589

    How many zones, and what's the heat load of the various zones?
  • Craig Benson
    Craig Benson Member Posts: 15
    Heat Loads and zone plans

    Based on the Uponor ADS software, my total house heat loss is 39,384 Btu/hr. Total heat radiant load = 34815, Downward total = 10496.

    There are 4 zones total:

    Basement slab is 1, 6-loop zone heating 1664sf with a heat load of 15,673.

    Main floor(attached) will be 3 zones, total of 29,638btu/hr

    The total of both floors together is 45,311btu/hr

    Add to this a Smart 60 indirect tank load??? and there we are.

    I don't know why a 110K boiler has been suggested to me, probably the salesman didn't want to mess up and under-spec so it was overkill. I will also have a woodstove in the great room for supplemental heat and plan on using it often. Once the slab and ICF basement are heated, that heat sink should serve to get us through any long cold snaps by serving as a "resevoir" correct? That would allow the boiler to concentrate on the main floor and alleviate some of the worst case scenario load issues with a smaller boiler I would think.

    Attached is a Warmboard plan, thanks again for all the help. It is very much appreciated.
  • Craig Benson
    Craig Benson Member Posts: 15
    Zone sizes

    The smallest zone is the Great Room with heat loss of 8755btu/hr. This is also the room where the woodstove will be located.

    Solo 60 specs: Input modulation 16-60MBH, DOE 54MBH, I=B=R 47MBH

    Solo 110 specs: Modulation 25-97, DOE Heating Capacity 87MBH, I=B=R 76MBH

    Smart 50 indirect calls for boiler output of 140K and Smart 60 jumps up to 270K

    I don't completely understand the domestic priority control. When the indirect calls for heat does the boiler automatically provide for a maximum temperature and flow to be provided for the tank? So if the boiler is barely running and outdoor reset is calling for 105* water then does the boiler ramp up to say 200* to supply the tank?

    Does the controller add a specific number of degrees to the reset temp or does it go to full capacity? Just trying to wrap my head around the amount of automatic operation to expect out of the system.

    Thanks for your info and especially patience!
  • Tony_42
    Tony_42 Member Posts: 37
    DHW priority

    Goes to 100% fire to the IDWH only, 190 degrees supply temp. Returns to ODR target when satisfied.

    The inputs listed for IDWH's are optimum, not necessary. I've fired tons of 40's & 60's with everything from 80k to 200k input boilers and have a 30 fed by a PS60 with no problems.

    Size your boiler to the heat load and install a water heater big enough to handle the "dump load".
  • cattledog
    cattledog Member Posts: 60
    Solo 110 minimum fire modulation


    Be careful with the TT Solo 110 minimum fire expectation. Unless TT has changed something in the past few years, it would appear that you will be somewhere above 35 Kbtu/h at miniumum fire and the actual turndown is more like 3:1 than 4:1.

    This data was taken two years ago on two different units using gas meter clocking. The issue of published minimum fire specifications may involve differences between minimum fan speed in European vs North American units.

    If you oversize and are counting on the minumum modulation with a TT 110 I would recommend getting someone to guarantee the perfomance.
  • Craig Benson
    Craig Benson Member Posts: 15
    Leaning more and more towards Solo60

    Even though it was an eye opener of a cold morning today at minus 18 degrees F, I am still a little reluctant to go with a boiler that won't modulate low enough for the "shoulder seasons" you guys suggest.

    By manipulating my ADS parameters to a -5* minimum and 22mph wind I still only get to maximum loss of 45Kbtu/hr

    I also just bought and will be installing very shortly for construction heat a 25Kbtu/hr woodstove and plan on relying heavily on it throughout the year because I can cut wood waaaaay, cheaper than propane and it is something I enjoy much more than writing out checks each month!

    Thanks for all your help and suggestions. This board is a lifesaver since I am so isolated from any "real" professional radiant plumbers.
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