Sump pump won't stop

[jmerica]

I've replaced a sump pump in my basement with one of the same make and model. However...the pump will not shut down when the water level drops. It has a diaphragm switch, and the troubleshooting material said (if the discharge pipe included a check valve, which it does) to drill a 3/16 hole in the pipe about two inches above the discharge connection. It still will not shut down. Anybody have an idea what I may be doing incorrectly?

[PLUMBER RICK]

does the pump actually pump out the water and lower the level of the pit?

the pump literature should give you the on and off levels of the pump.

the 3/16'' hole is important as it prevents the pump from getting an air lock since a check valve is required and is insatlled.

rick.