Grundfos cu301

[Mark Bloxom]

Terry, I recently saw the article you wrote on this controller. I have one and it is stuck on 100 PSI, the controller won' t change. You commented that the variable speed pump could be hooked straight to the power supply. If so what would the pressure be without the controller, wouldn't it still be running wide open? I really need a very low flow because its not that good of a well and it just runs to a 1000 gallon tank that I use for watering grass with another pump. Also could I put a variable speed motor controller on the power supply and adjust flow/ pressure that way.

 

[Reach4]

Normally you control a pump feeding an atmospheric tank with a float switch. No pressure switch. That SQE pump does not seem to be a good pump for the job that you need done. Could you have put a 4 inch pump down there?

Do you feel you need to throttle the pumping rate? If so, you could do that with a partially closed ball valve, but you must make sure that the valve never fully closes.

I don't know if there is a way to trick that controller to run the pump as slowly as it will go. Maybe you could simulate the sensor saying that the pressure is high, and the controller would slow the motor. I would not know how to do that.

 

[Sponsor]

 

[Valveman]

Like Reach says you can just run that pump without the controller if it is just filling a 1000 gallon tank. You can either manually turn the pump on and off as needed, or use a float switch in the tank.

If you need the pump to operate at a pressure and turn itself on and off as needed, you will need a regular pressure switch in place of the CU301 controller. But then you also will need a very large pressure tank, or a Cycle Stop Valve and you can stay with the little pressure tank you have.