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Pump sizing

BMurrins
BMurrins Member Posts: 45
in Radiant Heating
Hi all,

I’m trying to size a pump for a twin boiler setup. I’ve done the math and I need ~32 gpm at 16 ft of head. Currently we have 007s on the supply of each boiler but they’re undersized and we’re having trouble heating the apartments on the end of the loop. I’d like to do it right and pump away from the eliminator/expansion tank.

The 2400-45 looks good but taco doesn’t have 2 in flanges that fit the pump. Their largest flange goes to 1.5”. 

Would I be creating any issues using 1.5” flanges?


Comments

  • hot_rod
    hot_rod Member Posts: 23,400
    How did you come up with the pump size. It’s a big jump from an 007 to a 32 gpm pump

    The B&G PL series has about that size
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
  • EdTheHeaterMan
    EdTheHeaterMan Member Posts: 9,401
    edited November 2022
    Is this the same boiler room as the one we talked about before in "Confusing Setup" https://forum.heatinghelp.com/discussion/189443/confusing-setup# ?
    If you are accurate in your GPM and pump head calculation, and the pump you selected is correct, and the largest flange available is only 1-1/2" then you can use reducing couplings, or a bushing on one side and a reducing coupling on the inlet of the pump, to get you there. Are you removing the twin 007 pumps in favor of a single larger pump?

    Edward Young Retired

    After you make that expensive repair and you still have the same problem, What will you check next?

  • BMurrins
    BMurrins Member Posts: 45
    Hey Ed, no this is a different boiler room. Less confusing setup thankfully. Yes I’m removing the twins in favor of a larger one.

    I sized it based off of the “zoning made easy” that you shared with me. 
  • BMurrins
    BMurrins Member Posts: 45
    hot_rod said:
    How did you come up with the pump size. It’s a big jump from an 007 to a 32 gpm pump The B&G PL series has about that size
    Thanks for the recommendation! Hadn’t considered this. Going to look into it
  • EBEBRATT-Ed
    EBEBRATT-Ed Member Posts: 16,492
    The 1 1/2" flange will be fine. If the pump is selected correctly the flange size could well be smaller that the system it connects to. It's all figured into the pump head and flow rate and it will be fine
  • hot_rod
    hot_rod Member Posts: 23,400
    edited November 2022
    How were the 007 overcoming that 16’ of head? The gpm doubles, but the head didn’t by going from two to one circ, unless the 007,s were in series somehow?
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
  • BMurrins
    BMurrins Member Posts: 45
    hot_rod said:
    How were the 007 overcoming that 16’ of head? The gpm doubles, but the head didn’t by going from two to one circ, unless the 007,s were in series somehow?
    That’s just the problem. They weren’t. The apartments on the end of the loop have trouble getting warm. 
  • hot_rod
    hot_rod Member Posts: 23,400
    If you have the budget get an ECM style circ where you can dial in exactly what you need. If there are zone valves in the units you want a delta P style.

    If you do have zone valves and switch to a fixed speed high head, you should add a pressure bypass or you will get some high velocity, possibly push open some zone valves. The 007s are flat curves circs, which work great with zone valves.

    Notice the steep curves on those PL series They won’t play well with zone valves.
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
  • BMurrins
    BMurrins Member Posts: 45
    No zone valves on this system. 9 unit apartment building by the way.

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