ft(H2O)

Jamie_6

When calculating the proper pump size for a radiant panel do you add up all the individual head losses per loop to determine the entire systems ft(H2O)?

Thanks,

Jamie


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Alan(CaliforniaRadiant)Forbes

Pump head

No, the figure you want is the most restrictive loop. That, together with the total gpm for the system will determine the pump you need.

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ALH_4

Head Loss

It's just like electricity. Circuits in parallel have equal head loss and additive flow rates. Circuits in series have equal flow and additive head loss.

If you keep the loops close in length when installing the tubing, the math is a lot easier. You can assume all the loops are approximately the same. Be sure to account for distribution piping to remote manifolds.

-Andrew

Jamie_6

Then according to the Wirsbo ADS Radiant Design Summary the total system USGPM is 5.2 @ 8.1 ft(H2O).

And according to Wirsbo ADS head loss calculator the most restrictive loop has 3.2 ft(H2O).

I'm a little confused though. When sizing my pump for the radiant panel I use the panel’s ft(H2O) not the systems right? Then why does Wirsbo give you the ft(H2O) calculated?


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ALH_4

Well

There are only so many circulators from which to choose. According to the data you posted you're ok with one Grundfos 15-58. There are 3 speeds so you can slow it down if you choose.

Are you taking valves into account? Is this a single circulator system with differential pressure valve and zone valves?

-Andrew