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schunter 04-28-2011 10:23 PM

use 1hp control box on 3/4hp well pump?
Wondering if I can use a 1hp rated well control box with a 3/4hp submersible well pump? I bought the wrong one and its too late tonight to take it back. Wife really wants her shower!
Its a 220v in ground pump. 3 wires coming out of the well casing and 2 plus a ground coming from the house.

micromind 04-28-2011 11:42 PM

If the control box has one capacitor (a round thing with two wires, usually about 1" to 1-1/2" dia., and 2"-3" long), it'll very likely work. One problem will be that the overload is set for a 1HP motor, and won't protect a 3/4HP. If anything bad happens (like low voltage), the motor will burn up before the overload will trip.

The capacitor is also meant for 1HP, but it'll likely start a 3/4HP.

If the control box has two capacitors or one with 3 leads, it very likely won't work with a 3/4HP motor. This is because the second capacitor is used when the motor is running, not just to start it. Using the wrong run capacitor will cause too much current, and will eventually burn up the motor.


schunter 04-29-2011 08:30 AM

Micromind, thanks for the reply. The control box only has 1 capacitor and I went ahead and hooked it up last night. It worked fine but I think I'm gonna go get the 3/4hp one today. Really just a guess, but I'm a little concerned that the lower resistence on the 1hp may be bad for my pump. Really dont want to burn it up since its about 350' down.

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