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Monoflo tees

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Mitch_4
Mitch_4 Member Posts: 955
in THE MAIN WALL
and the system has monoflo tees in it. Never had one before as hydronics is a new avenue for me. I want to make sure the pump is correct as the old one is shot. I cross referenced it to the equivalent Grundfos, but am curious as to how these tees affect the pumping requirements in a system.

Are the additional factors to consider, how do calculate if I cannot cross reference.

Thanks for any information.

Mitch

Comments

  • Uni R_2
    Uni R_2 Member Posts: 589
    If this is for a modcon...

    If this is for a modcon and the customer wants to minimize fuel consumption, you may want to consider repiping to get rid of them - ideally homerun. I say that because those diverter tees will likely cost at least 10°F in higher return temperatures to the boiler and that will affect efficiency. This is because monoflo systems have such high flow requirements that they dilute the branch's ΔT. With a conventional boiler, this works for you, with a modcon it works against you.

    Low head, high flow is how these systems operate. I have yet to see a Cv rating for an "open" diverter tee, so I really wonder how people do calculate these.

    3 speeds make it easy, use the slowest speed that still heats all the branches uniformly.
  • Mitch_4
    Mitch_4 Member Posts: 955
    thanks

    > If this is for a modcon and the customer wants to

    > minimize fuel consumption, you may want to

    > consider repiping to get rid of them - ideally

    > homerun. I say that because those diverter tees

    > will likely cost at least 10°F in higher return

    > temperatures to the boiler and that will affect

    > efficiency. This is because monoflo systems have

    > such high flow requirements that they dilute the

    > branch's ΔT. With a conventional boiler,

    > this works for you, with a modcon it works

    > against you.

    >

    > Low head, high flow is how these

    > systems operate. I have yet to see a Cv rating

    > for an "open" diverter tee, so I really wonder

    > how people do calculate these.

    >

    > 3 speeds make

    > it easy, use the slowest speed that still heats

    > all the branches uniformly.



    No the upgrade will not be a mod con..tried, but they have a very limited budget..small home, CI atmospheric.

    Low head and high flow is what I am looking for, are the references or formulae for these?

    Removing them will not be done...they can barely afford the boiler, and I am cutting my line to do it or they freeze this winter...both were "downsized" from a factory that cut its force 70%, doing what I can..
  • Mitch_4
    Mitch_4 Member Posts: 955
    thanks

    No the upgrade will not be a mod con..tried, but they have a very limited budget..small home, CI atmospheric.

    Low head and high flow is what I am looking for, are the references or formulae for these?

    Removing them will not be done...they can barely afford the boiler, and I am cutting my line to do it or they freeze this winter...both were "downsized" from a factory that cut its force 70%, doing what I can..
  • Uni R_2
    Uni R_2 Member Posts: 589
    My limited experience...

    I had a B&G Series 100 on my monoflo system - 1.25" main with approx. 15 0.75" dia. branches leading to fintube HWBB. Calc'd heatloss was 57K, boiler was 0.65gph with pretty low efficiency.

    I replaced it with a 15-58. Worked perfect on speed 2, speed 1 could probably work on a small enough system, but not all branches got heat on mine, particularly the upstairs. In the spring when only the basement and lower rooms are chilled speed 1 actually does the trick...

    The 15-58 or something similar should be a pretty safe bet.
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