Combi Boiler System Installation Help

Discussion in 'Boiler Forum' started by Reicherb, Sep 4, 2021.

  1. John Gayewski

    John Gayewski In the Trades

    Joined:
    Aug 7, 2021
    Location:
    Iowa
    I think your taco 0015 will be oversized. That said I wouldn't be afraid to over size. Try it and let us know what your delta t is. If you end up with 5 or 10 degrees of delta you know it's over sized. The only problem would be short cycling.
     
  2. fitter30

    fitter30 Well-Known Member

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    Feb 2, 2020
    Occupation:
    Retired service tech
    Location:
    Peace valley missouri
    1" secondary loop & to the six zones
    3 /4" to the two zones
    by not connecting make to a perminate line if a leak develops glycol will not get deluted and a backflow device is not needed
     

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  3. Reicherb

    Reicherb Member

    Joined:
    Nov 7, 2013
    Location:
    Linden, MI
    Do you think a 007 is too small? Based on everything I've read slow flow is preferred.

    Thanks for the drawing and suggestions!
     
  4. Dana

    Dana In the trades

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    Jan 14, 2009
    Location:
    01609
    A Taco VR1816 won't break the bank, and offers many more tweaking options. It's about $100 more than the dumbest low efficiency 007s, ~$70 more than an 007e. (Gayewski won't like it, but he's neither paying your power bill nor fully designing your system.) In fixed-speed mode the VR1816 behaves roughly like the 003 when set to minimum speed, but roughly like the 0015 when set to maximum speed, with a whole lot of other stuff in between. But in most systems using on modes other than fixed speed will be more optimal.

    In a well designed system the pump would be running a VERY high duty cycle, and a dumb 007 or 0015 would be chewing through a lot of power to no good end. If you have 5 cent electricity that might be no BFD, but in my area residential retail electricity has edged north of 25 cents/kwh, and annual circulator power use has become QUITE relevant for radiant heating systems. Like mileage, your electricity price may vary.

    As a general observation, design by web forum is not the best approach to fully optimizing the system. At best it can (hopefully) steer you away from expensive disaster designs requiring major re-work and component swaps to get it do deliver what you want. And even the best designs can be thwarted by incompetent installation. Hydronic heating is not a mere "plug-and-play" exercise in plumbing, hooking up the right ga-zintas into the right ga-zoutas. (Sorry if that antique TV reference is too obscure. :) )
     
  5. fitter30

    fitter30 Well-Known Member

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    Feb 2, 2020
    Occupation:
    Retired service tech
    Location:
    Peace valley missouri
    Went to the UK once for a job went over with four engineers before picking a pump, we in the states pick a pump trim the impeller ( 3 ph with a vfd) there line voltage because cost of electric.
     
  6. John Gayewski

    John Gayewski In the Trades

    Joined:
    Aug 7, 2021
    Location:
    Iowa
    Agree, remote designs aren't great. We had a 3 million dollar house (in Iowa 3 million is crazy) whose designer was a professional hydronic designer. The guy who built the system from our company followed the design, being as it was from a professional. He ended up changing many things after performance wasn't as expected, and yes the pumps were one of the things that didn't line up.

    If you over size a pump and then balance it down your amperage draw goes down. There by using less electricity. The pump can run at full speed all it wants but it's moving less water. This keeps the components cool and by passes the complexity of a vfd.

    People who sell vfds love to sell all of the "benifits" and convince you that you need to change into these pumps. They bank on people not quite knowing how pumps work.
     
  7. fitter30

    fitter30 Well-Known Member

    Joined:
    Feb 2, 2020
    Occupation:
    Retired service tech
    Location:
    Peace valley missouri
     
  8. Reicherb

    Reicherb Member

    Joined:
    Nov 7, 2013
    Location:
    Linden, MI
    Thank you very much!

    I'm too cheap to pay for an actual design. I went through the same process on my house (baseboard radiant) and got excellent advise here. A few years later, everything is working very well.
     
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