Troubleshooting Troubleshooting Submersible Pumps Fuse overload or circuit breaker trips when motor is started Cause of Trouble 1. Incorrect line voltage. How to Check Check the line voltage terminals in the control box (or connection box in the case of the two wire models) with a voltmeter. Make sure that the voltage is within the minimum-maximum range prescribed by the manufacturer. 2. Defective Control Box (a) Defective wiring. (b) Incorrect components. Check out all motor and power-line wiring in the control box, following the wiring diagram found inside the box. See that all connections are tight and that no short circuits exist because of worn insulation, crossed wires, etc. Check all control box components to see that they are the type and size specified for the pump in the manufacturers’ literature. In previous service work, the wrong components may have been installed. (c) Defective starting capacitor (skip for two wire models). Using an ohmmeter, X1000 scale, determine the resistance across the disconnected starting capacitor. When contact is made, the ohmmeter needle should jump toward 0, and then drift back slowly toward infinity. No movement indicates an open capacitor, Iow resistance means that the capacitor is shorted. (d) Defective relay (skip for two wire models). 3. Incorrectly wired pressure switch. Using an ohmmeter, check the relay coil and contacts. Their resistance should be as shown in the manufacturer’s literature. Check the wiring at the pressure switch. How to Correct If the voltage is incorrect, contact the power company to have it corrected. Rewire any incorrect circuits. Tighten loose connections. Replace worn wires. Replace any incorrect component with the size and type recommended by the manufacturer. Replace defective starting capacitor. If coil resistance is incorrect or contacts defective, replace relay. Make sure all line, load and ground connections in the switch match the diagram. 4. Defective motor winding or cable: (a) Shorted or open motor winding. (b) Grounded cable or winding. Check the resistance of the motor winding by using an ohmmeter on the proper terminals in the control box (see manufacturer’s wiring diagram). The resistance should match the ohms specified in the manufacturer’s data sheet. If it’s too low, the motor winding may be shorted; if the ohmmeter needle doesn’t move, indicating high or infinite resistance, there is an open circuit in the motor winding or cable. Ground one lead of the ohmmeter onto the drop pipe or well casing, then touch the other lead to each motor wire terminal. If the ohmmeter needle moves appreciably when this is done, there is a ground in either the cable or the motor winding. 5. Pump locked. Check the line amps before the trip. If amps are twice normal, or higher, pump is probably locked. If the motor winding is defective—shorted or open—the pump must be pulled and the motor repaired. Pull the pump and inspect the cable for damage. Replace damaged cable. If cable checks OK, the motor winding is grounded. Pull pump, disassemble from motor and check which one is locked. Replace one, or both, if defective. 3/26 800-356-5130 | [email protected] | bakerwatersystems.com 357 Troubleshooting