What if I told you...

[Mandelstam]

(for sure was a little mind boggling for me to realize... But only true for centrifugal pumps, like a return pump)

 

[Diesel]

Explain?

 

[McArcher]

And it only applies to AC pumps

 

[McArcher]

Also, if you restrict it too much, efficiency goes way down. The peak efficiency point is usually near the middle of the curve.

 

[Grey Guy]

Check it out with a leaf blower. When the end is blocked, the motor speed increases dramatically. Nice to see you got hold of some good information. Would like to know more about the flow on D.C. pumps.

 

[Water Dog]

Definitely true for AC pumps... as an example, look at @d2mini ’s big Lifereef skimmer thread over on RC. People are running Fluval SP4s rated at 88 watts on a 24” Lifereef skimmer. With all the elbows and restriction because of the venturi, they’re only drawing 50 watts.