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How do I know the system circulator is the right fit

Le JohnLe John Posts: 140Member
I have roughly 75 feet of baseboard over three separate zone valves. How do I select the best circulator?

Zone 1 26 feet
Zone 2 18 feet
Zone 3 30 feet

Comments

  • ZmanZman Posts: 5,247Member
    I has more to do with the pipe size and length.
    "If you can't explain it simply, you don't understand it well enough"
    Albert Einstein
  • SnowmeltSnowmelt Posts: 1,101Member
    btu's of the zone divided by 500 x delta tee ( that gives your g.p.m. )
    then to get your head pressure you take the total length of pipe (longest zone) then you multiply by 1.5 elbows and other fitting) divided by .o4 that will give your feet of head.
    then use the charts of the pump manufacture to give your pump size .
    file:///C:/Users/u192772/AppData/Local/Temp/SelectingCirculators-1.pdf
  • Le JohnLe John Posts: 140Member
    Thank you @Snowmelt @Zman the size of baseboard itself is 3/4 copper pipe but the piping in the system to the baseboards are 1/2 inch
  • SuperTechSuperTech Posts: 938Member
    That's really odd. How is this piped? Is it a monoflo system? Maybe all of the baseboards are run in a home run to a manifold at the boiler?
  • Le JohnLe John Posts: 140Member
    @SuperTech 3 separate zones - each with a supply and return. The piping in the walls are 1/2 inch.
  • SuperTechSuperTech Posts: 938Member
    I just can't see that functioning correctly. Are you zoning with circulators or zone valves. Can you please post pictures of the boiler and piping?
  • hot_rodhot_rod Posts: 11,857Member
    If the baseboard is sized correctly, your 30' zone may require 15,000 BTU/hr. (500 btu/ft)
    That is possible with 1/2" copper. The length of the piping, number of fittings should be in the head calculation to size the circulator.
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    The magic is in hydronics, and hydronics is in me
  • Le JohnLe John Posts: 140Member
    @SuperTech - a Grudfoss UPS1558FRC circulator as the system pump feeding three Honeywell Zone Valves. I'm not at the property today but will post pictures when i get back there on the weekend.
  • Le JohnLe John Posts: 140Member
    @hot_rod how do I calculate the length of piping, number of fittings that are in the walls?
  • hot_rodhot_rod Posts: 11,857Member
    Le John said:

    @hot_rod how do I calculate the length of piping, number of fittings that are in the walls?

    Probably estimate the distance but guesstimate the fittings. I think Taco suggests a multiplier piping length X 1.5 to get a ballpark #

    The majority of the time a small multi speed 15-58, or other brand equivalent, covers a wide range of residential applications.
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    The magic is in hydronics, and hydronics is in me
  • pecmsgpecmsg Posts: 895Member
    Why 1/2" Supply and return lines?
  • Le JohnLe John Posts: 140Member
    @pecmsg The supply and return manifolds are 1 inch but gets reduced to 1/2 inch after the zone valve. The heating loops in the entire house was done in 1/2 inch copper. I don't know why.
  • Solid_Fuel_ManSolid_Fuel_Man Posts: 1,691Member
    There is nothing wrong with using 1/2 pipe to smaller zones. We do it all the time with panel radiators. As long as you have adaquite flow per the zone size (30' fin tube in your case). The smaller piping does create extra head, but most residential size systems are short enough that most reasonable sized circulators have no problem supplying the required flow.

    No reason to always use 3/4 pipe, it is just most commonly used.
    Serving Northern Maine HVAC, and Controls
  • Le JohnLe John Posts: 140Member
    Thanks @Solid_Fuel_Man so is the Grundfoss UPS 15-58FRC a good pump for the application? I thought based on the formula above I needed something like an Alpha 2 1558 or a Taco VT2218?
  • SuperTechSuperTech Posts: 938Member
    Both pumps are you mentioned are great and can cover a wide range of flow requirements. I'm a fan of both pumps but I have found that the Alpha is great for zone valve applications.I suppose that just because the 1/2" pipe is unusual doesn't make it completely wrong.
  • ZmanZman Posts: 5,247Member
    There is nothing wrong with 1/2" supply and returns, especially since your largest zone is only ~15k/btu.

    If your 15-58 is working well, I don't know that I would bother changing it. You can set it on the lowest speed that will give you satisfactory heating. A 20 degree supply/return delta t would be a good indication.

    The other circs you mentioned would be a nice upgrade and would save a few bucks in electricity.
    "If you can't explain it simply, you don't understand it well enough"
    Albert Einstein
  • Solid_Fuel_ManSolid_Fuel_Man Posts: 1,691Member
    I bet even on the lowest setting, there the delta T will be less than 10 degrees.
    Serving Northern Maine HVAC, and Controls
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