Troubleshooting

Diagnosis: An ‘O_C’ (Over Current) fault on a Phase Tech SubMonitor indicates the motor’s current draw has critically exceeded its Service Factor Amps (SFA) rating. This is a protective shutdown caused by severe mechanical binding in a worn pump or a catastrophic electrical failure, such as degraded and shorted motor windings. Professional diagnosis with a […]

Diagnosis: A Uv1 fault on a Yaskawa iQpump drive signifies a DC Bus Undervoltage, most often triggered by a sag in the incoming utility power or inadequately sized wiring. This condition starves the drive of energy, forcing the motor to draw excess current, which can lead to overheating and damage to windings and bearings. Troubleshooting

Diagnosis: A U_C (Under Current) fault on a Phase Tech SubMonitor VFD indicates the pump motor is no longer under a proper water load. This is typically caused by the well running dry, which starves the pump, or a catastrophic mechanical failure like a broken pump shaft. Immediate diagnosis is critical to prevent permanent motor

Diagnosis: A Grundfos CU 301 ‘Overvoltage’ fault indicates the incoming power supply has exceeded the 280V safety limit, triggering a protective shutdown of the SQE pump. This is most often caused by utility grid issues, such as a failing neutral conductor, or incorrect transformer tapping. Immediate diagnosis is critical to prevent permanent damage to the

Diagnosis: A Grundfos CU 301 ‘Overload’ error indicates excessive current draw from the SQE pump, typically caused by mineral buildup (iron or manganese) creating mechanical friction inside the pump’s hydraulic stages. This condition requires a licensed professional to pull the pump from the well for an acid wash or replacement of the hydraulic end. Verifying

Diagnosis: A ‘Sensor Fault’ on a Grundfos CU 301 controller indicates a failure of the 4-20mA pressure transducer. This is typically caused by physical damage from water hammer or ice formation, leading to erratic pump operation. The repair involves electrically isolating the system, depressurizing the plumbing, and replacing the faulty sensor with a new OEM

Diagnosis: The ‘No Contact’ error on a Grundfos CU 301 control box indicates a failure in the power line communication (PLC) signal to the SQE submersible pump. This is most often caused by a faulty waterproof splice in the power cable or physical damage to the wire itself, which interrupts the data signal traveling between

Diagnosis: A Goulds Aquavar SOLO F01 or F02 fault code indicates a severe overcurrent or short circuit condition, typically caused by a failed motor winding or a compromised submersible well pump cable. Troubleshooting requires electrical testing with a megohmmeter and often involves pulling the pump to inspect and replace the motor or cable splice. In

Diagnosis: The Goulds Aquavar F03 fault code signifies a Locked Motor or critical Overload condition. This is most often caused by a physically seized pump wet end due to sand infiltration, debris, or internal bearing failure. A professional repair involves pulling the pump from the well to either manually free the rotor or, if internal

Diagnosis: The Goulds Aquavar F04 fault indicates the variable frequency drive (VFD) is receiving insufficient line voltage, typically below 190V on a 230V nominal system. This is often caused by utility power sags, undersized wiring, or loose connections, which can force the motor to draw excessive current, leading to overheating and damage. Troubleshooting involves verifying