A sudden drop in water pressure or continuous, non-stop operation of a water pump is one of the most common challenges in building utilities and industrial fluid transport lines. When a pumping system drops out of automatic mode, besides producing annoying noise and causing a sudden surge in power consumption, extra stress is applied to the pump’s internal components, significantly increasing the risk of severe damage to the motor windings.

In this exclusive article from Fidar Energy, we aim to analyze 7 key causes of pressure drops and continuous pump operation by examining hydraulic parameters and auxiliary components, and introduce practical solutions to resolve these issues.

Troubleshooting Control and Hydraulic Components of the Pump

Pumping systems require complete synchronization between mechanical parts and controllers to operate accurately and shut off the flow on time. Disruption in this harmony occurs due to the following reasons:

1. Pressure Switch Malfunction

The set-control or pressure switch acts as the primary commander of the pump, issuing a stop command once the required pressure threshold is met. If the calibration spring slips out of standard settings, the sensor inlet becomes clogged with debris, or the electrical contact points burn and weld together, the switch fails to send the stop signal, causing the pump to run continuously.

Solution: First, disconnect the power supply, remove the pressure switch cover, and clean/smooth the contact points. If the problem persists, adjust the pressure differential screw (delta) or replace the switch entirely.

2. Worn Out or Punctured Pressure Tank Bladder

The expansion tank prevents frequent pump cycling by storing air and water under pressure. If the rubber bladder inside the tank tears or punctures, the air cushion is lost, destroying the compressibility needed to maintain pressure behind the automatic switch.

Solution: Press the valve pin at the top of the tank; if water comes out instead of compressed air, it is a definitive sign of a punctured bladder requiring replacement.

3. Air Binding and Trapped Bubbles in the Pump Casing

Air entering the suction pipe or internal pump casing causes a severe drop in pressure. Because air is compressible—unlike liquids—the pump impeller cannot generate enough head to trigger the automatic pressure switch.

Solution: Perform a priming operation. Open the bleed screw on the pump casing and pour in water until all air bubbles are completely purged.

Structural, Piping, and Fluid Head Loss Issues

Sometimes the pump and its control equipment are fully functional, but external factors along the fluid flow path cause severe pressure drops.

4. Check Valve Failure

A check valve allows fluid to flow in only one direction. If this valve gets stuck open due to sediment accumulation or wear and tear, the stored water pressure immediately backflows toward the inlet network or well right after the pump shuts off, causing the system to turn back on automatically.

5. Indirect and Hidden Leaks in the Distribution Network

Small leaks in concealed piping, siphons, or plumbing fixtures lead to continuous pressure loss in the line. In this condition, the system can never reach the shut-off pressure setpoint.

Solution: Close all water outlets. If the pressure gauge starts dropping, it indicates a leak within the piping path.

Direct Impact of Motor Health on Pump Performance

The beating heart of any pumping system is its electric driver. Any drop in efficiency in this section directly affects the output head and discharge flow rate.

6. Damage and Power Drop in the Electric Motor

If the torque generated by the motor decreases due to voltage drops, bearing wear, or winding overheating, the rotational speed of the impeller (e.g., 2900 RPM) drops.

In residential and commercial applications, using a standard electric motor with weakened windings prevents the pump from reaching the set pressure, resulting in continuous running. On the other hand, in sensitive industrial environments such as oil, gas, and petrochemical industries—where the use of a standard explosion-proof electric motor is imperative—even the smallest drop in efficiency or motor seizure can lead to a sudden drop in fluid pressure and continuous pump operation.

Summary and Conclusion

Timely troubleshooting of water pumps not only prevents energy waste and high electricity bills but also avoids costly damage to the mechanical seal and complete burnout of the motor windings. By periodically checking the pressure switch, expansion tank pressure, and electric motor output, you can keep your pumping system operating at peak efficiency.

The technical experts at Fidar Energy are ready to provide specialized advice on system selection, head and flow calculations, and the supply of your industrial and building equipment.