During routine, high-intensity operation, standard ZW-series self-priming sewage pumps inevitably encounter malfunctions. What are the common faults associated with these pumps, and how should they be resolved? Below, the pump experts at Shanghai Shenyin Pump Manufacturing Co., Ltd. explain how to troubleshoot and fix these issues.
I. Motor fails to rotate
(I) Causes:
1. Motor is damaged;
2. No power supply;
(II) Solutions:
1. Repair or replace the motor;
2. Check and connect the power supply.
II. Pump fails to discharge liquid
(I) Causes:
1. Insufficient priming liquid;
2. Significant air leakage at a flange, valve, or pipeline section on the suction side;
3. Priming port or vent port cap is loose, or the gasket inside the cap is missing;
4. No liquid in the container or sump.
(II) Solutions:
Check each item individually and resolve the specific issue found.
III. Flow rate and head (pressure) do not meet specifications
1. Voltage is too low, preventing the motor from reaching rated speed;
2. Motor is rotating in reverse;
3. Bottom strainer is clogged, restricting flow;
4. Slow air leak at a suction-side flange, valve, or pipeline section, affecting the pump's vacuum level;
5. Liquid level in the container or sump is too low, causing intermittent air intake.
IV. Leakage at the connection between the motor and the pump
1. Leakage occurs only at startup and disappears during normal operation;
2. Continuous leakage during operation (possibly due to a damaged sealing device or a significant discrepancy between actual head/pressure and the pump's rated parameters).
(II) Solutions
1. Overfilling with priming liquid; this is not a malfunction;
2. Check the sealing device for damage and recalculate whether the actual operating pressure exceeds the pump's rated parameters. If the seal is damaged, consider repair or replacement; if there is a significant discrepancy in pressure parameters, consider re-selecting the pump model or adjusting the actual operating pressure. How to Troubleshoot Self-Priming Sewage Pumps