ZX / ZXL Clean Water Self-Priming Centrifugal Pump

Installation

1. When the pump and electric motor are directly coupled, ensure the coaxial alignment of the pump shaft and motor output shaft. The accuracy of the pump installation significantly affects the smooth operation and service life of the pump, so installation and alignment must be done carefully.

2. The pump coupling must be securely fastened with nuts, and the nuts must be locked to prevent loosening, which could cause the impeller to move improperly, leading to mechanical failure.

3. To maintain a certain amount of stored liquid for better self-priming capacity and to prevent dry friction of the mechanical seal, the pump inlet should be higher than the center line of the pump shaft.

4. Considerations for the installation of the suction pipeline:

   • A. The installation height of the suction port should not exceed 3.5 meters. If possible, the height of the suction port should be as low as possible relative to the water reservoir’s surface and the suction pipe length should be minimized with fewer elbows to reduce self-priming time and enhance self-priming function.

   • B. Valves, flanges, etc., in the suction pipeline must be carefully checked for air or liquid leakage; no air leakage is allowed in the suction pipeline.

   • C. To prevent the pump from sucking solid debris, install a filter on the suction pipe. The effective cross-sectional area of the filter should be 2-3 times the suction pipe’s cross-section, and the filter should be checked regularly.

   • D. The suction and discharge pipelines should each have their own supports. The pump itself should not bear the load of the pipelines.

5. During the installation of the self-priming pump, ensure the static grounding resistance of the pump and pipeline meets the required specifications.

6. Carefully check the pump casing and pipelines for any debris or contamination that could affect operation.

7. Align the pump coupling and motor coupling, ensuring the axial tolerance does not exceed 0.1 mm. Adjust the height difference between the pump shaft and motor shaft using copper or iron shims under the feet.

8. After 3-4 hours of operation, conduct a final inspection. If no abnormality occurs, the installation can be considered complete. During the test run, check the bearing temperature; it should not exceed 70°C.

9. If the pump bearing housing has a cooling chamber, a cooling liquid hose (Φ12) should be connected to the designated cooling port. The thread size is M12×1.25.

10. If a one-way valve is installed in the pump’s discharge pipe and the pump cannot discharge air during the self-priming process, a small vent pipe and valve should be added to the pump’s discharge port.

Operation & Running

1. For this series of self-priming pumps, high-quality calcium-based grease and 10# motor oil are used for lubrication. For grease-lubricated pumps, regularly add grease to the bearing housing; for oil-lubricated pumps, ensure the oil level is sufficient.

2. Check whether the liquid level inside the pump casing is above the upper edge of the impeller. If insufficient, add liquid through the filling port of the pump casing. Do not start the pump if the liquid level is inadequate, as it may damage the mechanical seal.

3. Check the rotating parts of the pump for any obstruction or collision.

4. Check the foundation bolts and connections to ensure no looseness.

5. Check the alignment and parallelism between the pump shaft and the motor shaft.

6. Check the suction pipeline for air leaks; if found, eliminate the leaks.

7. Open the suction valve slightly (do not fully open) and adjust the discharge valve.

Starting & Operation

1. Momentarily start the self-priming pump and check whether the pump shaft rotates in the correct direction.

2. Monitor for any abnormal noise or vibration during operation.

3. Observe the pressure and vacuum gauges. After a period of fluctuations, once the gauges stabilize, it indicates the pump has primed and is ready for normal operation.

4. During the self-priming process, closely monitor the pump’s temperature. If the temperature rises too much or the process takes too long, stop the pump and check for issues.

5. If the temperature is too high, stop the pump, allow the liquid in the discharge pipe to flow back into the pump, or directly add liquid through the filling port to cool the pump, then restart.

6. If the pump experiences strong vibration and noise during operation, it may be due to cavitation. This can be caused by excessive flow rate or high suction head. Reduce the flow rate by adjusting the discharge valve or lower the installation height of the pump if the suction head is too high.

7. If the pump stops during operation and needs to restart, slightly open the discharge valve (do not close it completely) to facilitate the removal of air from the discharge port during the self-priming process and ensure the pump starts under lighter load.

8. Check for any leaks in the pipeline system.

Stopping the Pump

1. First, close the discharge pipeline valve.

2. Stop the pump from rotating.

3. During cold weather, drain the stored liquid from the pump casing and the bearing housing’s cooling chamber to prevent freezing and damage to components.

Maintenance and Care

• The pump is designed for simplicity and durability. Generally, it does not require frequent disassembly for maintenance. However, any issues should be addressed promptly when they arise.

Main Maintenance Points

• Rolling Bearings: After prolonged use, when the bearings have worn down, they need to be replaced.

• Front and Rear Seal Rings: When the seal rings wear down, they need to be replaced.

• Mechanical Seal: The mechanical seal should generally not be disassembled unless leaking occurs. If serious leakage occurs at the bottom of the bearing housing, the mechanical seal should be inspected. When installing or disassembling the mechanical seal, handle with care and ensure the sealing surfaces are clean. Avoid knocking or damaging the faces. Leakage from the mechanical seal can often be caused by abrasion of the sealing faces, which can be restored by polishing them. Another cause of leakage is improper installation or deformation of the rubber O-ring (or cushion), which should be replaced if necessary.

Disassembly &Assembly Sequence

1. Remove the motor or disengage the coupling.

2. Remove the bearing housing assembly, check the radial clearance of the impeller and front ring, and check the impeller nut for tightness.

3. Remove the impeller nut, pull out the impeller, and check the radial clearance between the impeller and the rear seal ring.

4. Loosen the set screw of the mechanical seal, remove the dynamic ring part, and check the mating surfaces of the dynamic and static rings and the condition of the O-ring (or cushion).

5. Remove the coupling’s set nut and pull out the coupling.

6. Remove the bearing end cover and remove the bearings from the pump shaft.

7. Reassembly is done in the reverse order of disassembly.