First, the pump does not absorb water, but the vacuum gauge shows a high vacuum. Cause of failure: bottom valve is not open or blocked; suction pipe resistance is too large; water absorption height is too high. Remedy: Open or clean the bottom valve; clean or replace the suction pipe; reduce the water absorption height. Second, the pump does not discharge water, and the pressure gauge and the vacuum gauge pointer jump violently. Cause of failure: The amount of water injected into the pump is not enough; the inlet pipe leaks. Remedy: Fill the pump with water again; block the leak. Third, the sound inside the pump is abnormal, and it cannot absorb water. Cause of failure: large water absorption resistance; high water absorption height; suction pipe leakage; excessive flow, cavitation occurs. Remedy: Check the suction pipe and bottom valve; reduce the water absorption height; block the leak; adjust the water gate valve. Fourth, the pump does not produce water, and the pressure gauge at the outlet shows pressure. Cause of failure: The pump shaft is placed in the wrong direction; the resistance of the outlet pipe is too large; the impeller is blocked; the pump speed is not enough. Remedy: Correct the orientation; check the length of the water pipe or clean the outlet pipe; clean the impeller; increase the pump speed. Fifth, the pump vibration is serious. Cause of failure: The pump has cavitation and the impeller is unbalanced; the pump shaft and the motor shaft are not concentric and the anchor bolts are loose. Remedy: Clear cavitation; correct the balance of the impeller; correct the concentricity of the pump shaft and the motor shaft, and tighten the anchor bolts. Sixth, the pump flow decreases or the head drops. Cause of failure: The impeller or inlet and outlet pipes are blocked; the impeller of the seal ring is worn badly; the pump shaft speed is lower than the specified value. Remedy: Clean impeller or tubing; replace damaged seal ring or impeller; adjust pump speed to specified value. Seven, the power consumed by the pump is too large. Cause of failure: The packing pressure is too tight; the seal ring is damaged; the flow rate is too large. Remedy: Loosen the packing gland; replace the seal ring; close the outlet valve.