How to Perform Self-Diagnostics When a Fire Pump Malfunctions

Although fire pumps are widely used across many fields, many people believe they are prone to failure and that fire pumps are powerless to prevent it. In the automatic inspection cabinet of a fire pump, the centerline of the impeller outlet—that is, the centerline of the impeller outlet width—should align with the centerline of the volute inlet. If misalignment occurs, adjust by adding shims between the impeller hub and the shaft shoulder. The deviation between the two centerlines should be controlled within 0.5 millimeters. For pumps with high specific speed, a slightly larger deviation has minimal impact on performance. However, for pumps with medium to low specific speed, where the impeller outlet is narrow—for example, only 10 millimeters wide—a 1-millimeter deviation from the volute centerline significantly affects the fire pump's performance. After adjustment, it is recommended to control the deviation between the two centerlines (impeller and volute) within 5% of the impeller outlet width. Inspect and adjust the packing in the fire pump control cabinet, replacing it as required. Adjust the mechanical seal (refer to the manufacturer's instructions provided with the pump or consult the manufacturer). Fire gas pressurization equipment is categorized into different types based on various classification methods. With its fully sealed, leak-free, and corrosion-resistant characteristics, it is widely used in environmental protection, water treatment, firefighting, and other sectors for pumping various liquids. It is an ideal pump for creating leak-free, pollution-free workshops and factories. The pump types used in firefighting systems are similar, differing only in head and flow rate. Below is a brief description of common fire pump failures.

1. Fire pump fails to supply liquid or exhibits insufficient liquid/pressure supply, potentially caused by:

1. First verify if the fire pump's casing and inlet pipe are filled with liquid, ensuring proper priming and air purging.

2. Inspect the inlet pipe for air leaks at vent openings.

3. Check for incorrect motor wiring, which may cause abnormally low rotational speed.

4. Verify the discharge or pipeline pressure gauge is positioned correctly.

5. Inspect whether the impeller clearance has failed.

6. Check if the net positive suction head (NPSH) required for the fire pump has been compromised due to wear.

7. Examine whether system head loss is caused by friction.

8. Inspect valves or standard components at the inlet end for blockages.

9. Check for obstructions in the impeller and piping system.

10. Verify the rotation direction is correct.

Check the bottom valve installation for correctness.

12. Inspect the packing gland lubrication system for normal operation and abnormalities.

13. Check the impeller diameter and ensure it is correctly sized.

Second, if the fire pump exhibits excessive power consumption, inspect:

1. Check if the calibration shaft is bent.

2. Verify the wear ring is functioning properly.

3. Check for abnormal wear clearances in internal components.

4. Verify the impeller's operational direction is correct.

5. Inspect the pump casing for excessive piping stress.

6. Check the stuffing box for insufficient or improper packing.

If the fire pump requires fault diagnosis, contact the manufacturer to arrange repairs. Alternatively, you may purchase a new fire pump directly from the manufacturer.