Pump is humming but will not start, then trips the breaker or thermal overload

Safety first: Turn off the breaker and verify power is off. Capacitors can hold charge; discharge safely if you are qualified.

• Check shaft rotation: With power off, try to spin the motor shaft from the rear fan. If it spins freely, the start capacitor is a likely culprit.
• Inspect capacitor: Open the motor terminal box on the Saci pump and locate the cylindrical capacitor. Look for bulging, leaks, or burnt smell.
• Replace capacitor: Note the capacitance (µF) and voltage rating printed on the part. Replace with an identical, motor‑rated capacitor, wiring it exactly as before.
• Test run: Reassemble, restore power, and start the pump. If it still only hums, further motor diagnostics are required.

If you are not comfortable working with capacitors and live circuits, contact a qualified technician.