Troubleshooting an Old Irrigation Pump Motor That Won’t Run

A 15–20 year old irrigation pump in South Florida doesn’t start. The timer ticks (fuses good), but the motor is silent—no hum. Contacts were cleaned with sandpaper; still nothing. The pump is likely centrifugal.

Diagnostic Steps

1. Verify power at the motor: Use a multimeter to check for 120V or 240V at the motor terminals. Only do this if you’re qualified—240V can be lethal.
2. Check the capacitor: Many single-phase motors have a start/run capacitor that fails silently. A bulging or leaking capacitor needs replacement.
3. Test motor windings: With power off, check continuity and resistance. Open or shorted windings mean the motor is toast.
4. Consider replacement: At 15–20 years, a new pump ($200–400 plus labor) is often wiser than repairing an old motor.

Alternative: Eliminate the Pump

Check static water pressure without the pump. If you have 35–50 PSI from the municipal supply, you may only need to change sprinkler nozzles to lower-flow models and remove the pump entirely. This saves electricity and maintenance.