Pump Short Cycling: Pressure Switch Settings and Zone Flow Balance

Pump charges to 70 PSI, shuts off. Drops to 40 PSI in 2 min, kicks on. Sometimes stops charging at 40 PSI, drops to 10 PSI.

Normal vs. Abnormal

Matt: "Your pump should operate this way. When it drops to 40 PSI the pressure switch turns the pump on. When it reaches its set high pressure it shuts off. The normal range is 20 PSI between the high and low. (On at 40, off at 60) The problem of going down to 10 PSI and then off at 40 PSI is a pressure switch problem and should be repaired."

Cycling Cause and Fix

"The pump is producing more water than your sprinkler system needs. That's why it builds up and shuts off. This is called 'cycling'. By using larger nozzles or wiring 2 zones together you can utilize all the water the pump produces. This is a much better operating condition for the pump."

Improper cycling damages motor and wastes electricity. Increase zone flow (larger nozzles, combine zones) or widen pressure switch differential.