1. The import and export valve of the hot water circulation pump is not opened, the entry and exit pipe is blocked, and the abortion impeller is blocked. Solution to remove obstructions.

2. Pipelines and hot water circulation pump pumps are blocking the impeller, scale deposition, and insufficient valve opening. Remove the obstruction and re -adjust the valve opening.

3. Use the rated traffic. Adjust the traffic off the small outlet valve.

4. Democracy. Replace the leaf wheel.

5. The voltage of the centrifugal pump is low. Stabilize.

6. Pump bearing wear. Replace the bearings.

7. The suction of the centrifugal pump is too high. Reduce suction.