Pump Flow Switch

[the_dude]

Dude here....

I have a domestic hot water recirc pump 8GPM @ 17psi (40ft.w.c.)

I was thinking of using a flow switch to monitor the flow for a DDC system.

However, the flow switch imposes a pressure drop of approx. 3 psi.

I am a little worried of putting in a piping element that will inhibit the desired flow...

Any opinions?

[absrbrtek]

Use a pressure differential switch to prove flow.

[freonrick]

another option would be an electronic flow switch. the diff pressure switch would be all right if the city water pressure did not bounce up and down much causing false alarms. another way is a current sensor on the motor.