New Sprinkler Pump Short-Cycling: Pressure Switch Adjustment

A replacement pump short-cycles every 10 seconds during irrigation cycles. The old pump ran continuously. The system has a pressure tank.

Pressure Switch Adjustment Procedure

1. Locate the pressure switch (≈3" square box on the pump or tank tee).
2. WARNING: High voltage inside. Disconnect power before opening.
3. Remove the cover. Most switches have two adjustment nuts: the taller one sets cut-in pressure.
4. Turn the tall nut clockwise 1 turn to raise cut-in pressure.
5. Run the smallest zone (most prone to cycling). If cycling persists, add another turn.
6. Repeat until the pump runs continuously for several minutes.
7. Shut off irrigation; verify pump stops. If it runs on, back the nut off ½ turn.
8. Iterate until the pump starts/stops cleanly at desired pressures.

Check Pressure Tank Bladder

If adjustment doesn't cure cycling, the tank bladder may be ruptured. Depress the air valve (Schrader valve) on the tank: if water spurts out, the bladder is failed and the tank needs replacement.