18A-20A Main Breaker (Overload Circuit Protector) for 3HP Single Phase Control Box. This is the one near the center at the bottom of the control box. The secondary protector is the one near the side, 9A-10A, which can't likely go wrong.
"Trip Free" design, do NOT hold "ON" it during fault current condition!!
Avoid to install the control box in direct sun or in a hot area.
Protectors are made to protect the abnormal situation. When it tripped, it is most likely that there is a reason causing it to trip. To reset it, You must follow this process:
1) Shut off the main power.
2) Wait for 30 second for the protector to cool down.
3) Turn on the power to try the pump. Do NOT force it to reset while the power is on!
If the tripping is causing by a power surge, lightning or temporary low voltage, after resetting the protector, the pump should work again.
If the protector trips immediately or in less than 10 second after power on, there may be a short circuit in the drop wire or the pump is locked up. Do NOT push the reset while the power is on.
If the protector continues to trip several times in a month, you may change it. In the meantime check for the pressure tank's pre-charged pressure, 2-3 PSI lower than the cut on pressure set for the pressure switch. Check if there is air got in the pump due to leaky pipe, or broken tank bladder. Make sure an external check valve is installed under water level if a pressure tank is used.