What Are The Reasons Why The Water Pump Of The Constant Pressure Variable Frequency Water Supply Equipment Does Not Supply Water

May 12, 2025

1, Low speed of water pump:

Some users, due to damage to the original motor, randomly installed another motor to drive it, resulting in low flow rate, low head, and even no water supply. Secondly, mechanical failures of the water pump itself, such as loose fastening nuts between the impeller and pump shaft or deformation and bending of the pump shaft, can cause the impeller to move too much, resulting in direct friction with the pump body or bearing damage, which may reduce the speed of the constant pressure variable frequency water supply equipment water pump. Furthermore, the maintenance of the power machine is not effective, and the motor loses magnetism due to burnt windings. Changes in winding turns, wire diameter, and wiring methods during maintenance, or incomplete troubleshooting during maintenance, can also cause changes in the speed of the water pump.

2, Excessive resistance loss in the inlet and outlet pipes of water flow:

Some users have measured that although the vertical distance from the reservoir or water tower to the water source surface is slightly less than the pump head, the water lifting capacity is still small or unable to lift water. The reason is usually that the pipeline is too long, there are many bends in the water pipe, and the resistance loss of water flow in the pipeline is too large. In general, the resistance of a 90 degree bend is greater than that of a 120 degree bend, with a head loss of about 0.5-1 meter per 90 degree bend. The resistance of a 20 meter pipe can cause a head loss of about 1 meter. In addition, some users also arbitrarily change the inlet and outlet pipe diameters of the constant pressure variable frequency water supply equipment pump, which affects the head.

3, There is air in the inlet pipe and pump body of the water pump:

Constant pressure variable frequency water supply equipment

Before starting the water pump, it is not filled with enough water. Sometimes it appears that the water has overflowed from the vent hole, but the pump shaft has not been rotated to completely discharge the air, resulting in a small amount of air remaining in the inlet pipe or pump body. The horizontal section of the inlet pipe in contact with the water pump should have a descending slope of at least 0.5% against the direction of water flow. The end connected to the inlet of the water pump should be the highest and not completely horizontal. If lifted upwards, air will remain in the inlet pipe, reducing the vacuum level in the water pipe and pump, and affecting water absorption. The packing of the water pump has been worn out or compressed too loosely due to long-term use, causing a large amount of water to spray out from the gap between the packing and the pump shaft sleeve. As a result, external air enters the interior of the water pump through these gaps, affecting water lifting. The inlet pipe has holes due to long-term potential underwater corrosion on the pipe wall. After the water pump works, the water level continuously drops. When these holes are exposed to the water surface, air enters the inlet pipe through the holes. Cracks at the bend of the inlet pipe and small gaps at the connection between the inlet pipe and the water pump may allow air to enter the inlet pipe.

4, Electric rotor imbalance:

Due to the severe vibration of the water pump in the constant pressure variable frequency water supply equipment, or the imbalance of the electric rotor, or poor coupling, the bearings are worn and bent; It is also possible that some rotating parts may become loose or break; Perhaps it is due to unstable pipeline supports, etc. Measures such as adjustment, repair, reinforcement, and replacement can be taken separately for handling. Pipeline leakage or air leakage may result in loose nuts during installation. If the leakage is not severe, cement or cement slurry mixed with asphalt oil can be applied to the leaking or leaking area. Temporary repairs can be done by applying some wet mud or soft soap. If there is water leakage at the joint, the nut can be tightened by hand. Those with severe water leakage must be disassembled and reassembled. Overheating of the packing is often caused by the packing being pressed too tightly, preventing cooling water from entering the packing, or damaging the shaft surface. Appropriate measures can be taken to relax the packing and clean up blockages in the sealed pipes. The worn packing must be replaced with a new one. Soak in the engine oil before installation, and install it in circles with staggered cuts to reduce water leakage. After the last round of packing is installed, tighten the gland and adjust the tightness during operation. The reasons why the water pump does not suck or discharge water are often due to the bottom valve getting stuck, the water filtering part being clogged, the suction height being too high or the suction leaking, or possibly due to incorrect steering or blocked impeller flow channels. After checking one by one, measures such as repairing the bottom valve, removing blockages, correcting the steering, and cleaning the impeller can be taken separately.

5, Excessive suction:

Some water sources are deeper, while others have flatter terrain around them, neglecting the allowable suction range of the water pump, resulting in less or no water absorption. It should be noted that the vacuum degree that can be established at the suction port of the water pump is limited, and the suction range of absolute vacuum is about 10 meters of water column height, while the constant pressure variable frequency water supply equipment water pump cannot establish absolute vacuum. Moreover, excessive vacuum can cause the water inside the pump to vaporize, which is detrimental to the operation of the water pump. So each centrifugal pump has its maximum allowable suction stroke, usually between 3-8.5 meters. When installing a water pump, it is important not to only focus on convenience and simplicity.

6, Severe vibration or noise generated by the pump body:

Due to improper or excessive installation of the water pump, or damage to the motor ball bearings, the water pump spindle may be bent or not concentric or parallel with the motor spindle. The water pump should be installed stably or the installation height of the water pump should be lowered, the motor ball bearings should be replaced, the bent water pump spindle should be corrected, or the relative position between the water pump and the motor should be adjusted. Due to other factors, the bottom valve cannot be opened. Usually, it is due to the water pump being left idle for too long, causing the gasket of the bottom valve to stick, and the bottom valve without a gasket may rust. The bottom valve filter mesh is blocked; Or the bottom valve may cause blockage of the filter screen in the potential sludge layer in the water. The impeller is severely worn. The wear and tear of impeller blades over long-term use has affected the performance of the water pump. Gate valves and check valves with faults or blockages can cause a decrease in flow or even prevent water from being pumped out. Leakage in the outlet pipeline can also affect the amount of water extracted.