Another Dumb Newbie Question... CSV Bypass?

[DaveK01]

From what I've read, most of the CSV's reduce pump flow to around 1 GPM when the pump discharge is fully throttled. Unfortunately, newer pumps seem to have higher minimum flow requiremts.

Is it better to find a CSV that meets the minimum flow requirements, or would a properly sized bypass orifice work to provide the minimum required flow when the CSV is fully closed? I don't want to buy a bigger valve if it isn't needed!

 

[Reach4]

There are standard CSVs that pass 3 GPM. Expect to use a pressure tank about 3x as big.

 

[Sponsor]

 

[Craigpump]

Put a sleeve over the pump & motor to promote better cooling.

 

[Valveman]

You want to stay with the 1 GPM bypass in the CSV. That way as long as you are using more than 1 GPM the pump does not cycle and you can use a smaller tank. If the bypass is 3 GPM, anything less than 3 GPM usage, as with a 2.5 GPM shower, will cause the pump to cycle, and requires a pressure tank that is 3 times larger.

Just don't use a Franklin pump as they are the only ones who say their pump will not work down to 1 GPM. All other brands will work fine down to 1 GPM, and they have been doing so for 24 years now with CSV control systems. I really don't think the Franklin has a problem at low flow rates, as they use that same pump in their in-line series that has the little controller that works down to 1/5th of a GPM. But of course that in-line controller won't extend the pump life like a CSV will do, which is why they say they have a problem with low flow from a CSV, but don't have the same problem on their little controllers which work down to 1/5th of a GPM. Go figure!