Head loss for manifolds

sriche01

Quick question: When calculating head loss for a radiant loop, do you add the pressure loss of each loop together, or is it just one loop that is taken into consideration?

Thanks!

sriche01

To be clear, I mean a manifold of multiple loops in one zone…

Jamie Hall

It is the pressure loss in the one loop with the greatest loss. The pressures do not add up — but the flows do.

GGross

to add to that, you will have pressure drop for the supply and return piping, valves, the manifold itself, etc. you will add the pressure drop for all of the supply and return piping system and manifold, to the head of the loop with the greatest pressure drop. That will be your total head, then add the flow requirement for every loop on that manifold, that total flow, and total head number is your pump spec, assuming you are individually pumping that manifold.

hot_rod

The manifold will have some flow resistance, Caleffi shows 1.23Cv for combined S&R. So very small amount

On a high flow 3/4 snowmelt, you may want to run the pressure drop calc, and include that pressure drop of the circuit. And the glycol derate..

sriche01

Thanks guys! I appreciate the repsonses!