Does a closed loop have head loss?

[Tron87]

With water pushing down towards the pump from both ends and the loop having equilibrium and equal pressure to the tank, is there any head loss?

I would think that there is not except for one thing. I can only think that the pump pulling water down from the tank faster than it would be able to "fall" through the lines would eliminate the effect of that water helping to push the outgoing gallons on their way.

So what is going on with CL's?

Who says head and who says no way?

 

[Hop]

It's a small amount. Really not enough worth calculating, especially if you upsize the intake and return lines.

 

[areze]

head loss is a measure of resistance to flow. its name implies that its only from gravity, because thats a simple way to actually express it in a number. but resistance comes for simple friction in a tube(smaller tubes=more friction) and also from inefficient bends in the tubes. also, higher rate of flow will create more turbulance which is more resistance.

so no, there is no pressure differential to overcome, but that doesnt mean the water flows through with no resistance at all either.

typical closed loop probably has the equivilant of 1-4feet of "head" depending on the specific setup.

 

[xcreonx]

Turns in your plumbing also cause head loss. Try to minimize 90 degree elbows or flow restrictions for less pressure. Some people use flex pvc so there's no right angles in their plumbing.