How to Size Circulators

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How to Size Circulators

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cgregory

I'm coming up with total dynamic heads of 52.8' for a 330' half-inch Pex line and 52.5' for a 600' ¾" line. Those numbers seem way out of range for typical circulators. What am I doing wrong?

Zman

I think the article gives some good general sizing advise when most of the piping is unknown.
I would not size a new pex system this way. The manufactures have pressure drop charts that will be far more accurate.
Part of the problem you are encountering that your gpm's are not very realistic for radiant heat loops (loop lengths are also very long). It also looks like you are doubling the loop length in your calculation.

I would suggest starting a new post to inquire as the best way to size your system.

cgregory

Thanks! How do I start a new thread???

Erin Holohan Haskell

@cgregory - Just click on New Discussion at the upper right to start a new thread. Thanks!

HVACNUT

> @Erin Holohan Haskell said:
> @cgregory - Just click on New Discussion at the upper right to start a new thread. Thanks!

>>I don't see that op on my smart phone. ?

Erin Holohan Haskell

@HVACNUT - When you're signed in on the mobile app, you'll see a black and grey bar at the bottom. It has icons of an inbox, earth, star, and pencil. Click on the pencil and you'll be given the options to start a new discussion or poll.

JohnRooks

Great piece! Thanks. I just checked Google for the Syzer, and find that there is a program version available for free for Windows and Mac systems, from B&G. I have not tried it yet, but its 60mb, so its certainly large enough to be fully capable. Cheers

heritageproperties

cgregory, your pipes are too small!

John Ruhnke

John Siegenthaler has a great software called hydronics design studio. You can find it at Hydronicpros.com. You lay out the piping and manifolds in the software along with sizes and loop lengths. Then you can pick a pump from a list in the software plug it into the system and you get the flow rates and head pressure through the system. You can just keep trying different pumps in the system until you find one with the best results. You can also change pipe sizes and see flow rate changes. I find it the easiest way to pick a pump for the application along with all the right pipe sizes. I used it all the time. Its a great design software.