Installation Of Self-Priming Pumps

1. When the pump is directly coupled to the motor, attention must be paid to the coaxiality between the pump shaft and the motor output shaft. The accuracy of the installation significantly affects the pump's operational stability and service life; therefore, installation and alignment must be performed with great care.
2. The pump coupling must be securely fastened with a nut that is properly locked to prevent loosening; otherwise, axial movement of the impeller may occur, leading to mechanical failure.
3. To ensure a sufficient volume of liquid remains within the pump casing-thereby achieving optimal self-priming capability and preventing dry friction on the mechanical seal-the pump inlet must be positioned higher than the centerline of the pump shaft.
4. Regarding the installation of the suction pipeline:
A. The installation height of the suction inlet must not exceed 5 meters. Whenever conditions permit, the inlet should be positioned as low as possible relative to the lowest water level in the reservoir. Additionally, the suction pipeline should be kept as short as possible with a minimum number of elbows; this helps reduce self-priming time and enhances self-priming performance.
B. Valves, flanges, and other components in the suction pipeline must be strictly sealed to prevent air or liquid leakage; air leakage into the suction pipeline is not permitted.
C. Measures must be taken to prevent solid debris from entering the pump casing; a strainer should be installed on the suction pipeline for this purpose. The effective flow area of ​​the strainer should be 2 to 3 times the cross-sectional area of ​​the suction pipe, and the strainer should be inspected regularly.
D. Both the suction and discharge pipelines must be independently supported; the pump casing itself must not bear the load of the piping.
5. During installation, ensure that the static electricity grounding resistance for the pump and piping meets the specified requirements.
6. During installation, strictly inspect the pump casing and pipelines for debris such as stones or iron filings.
7. Adjust the installation clearance and coaxiality of the pump and motor couplings; the permissible deviation for coaxiality is 0.1 mm. Any height difference between the pump shaft and the motor shaft can be corrected by placing copper or iron shims under the mounting feet. 8. After the unit has operated for 3–4 hours, perform a final inspection; if no issues are found, the installation is considered complete. Monitor the shaft during the trial run.
9. For pump bearing housings equipped with cooling chambers, the cooling water connection is designed for rubber or plastic hoses with an inner diameter of 12 mm; the thread size is M12×1.75.
10. If a check valve is installed on the pump's discharge line and prevents the pump from successfully expelling air during the self-priming process, an air-venting pipe and valve should be installed at the pump outlet.