During the operation of the fire pump, the idling of the fire pump is not allowed. In fact, the fire pump will not cause damage within a short time of idling (within 1 minute).
But what are the reasons that caused the fire pump idling?

The reasons for the idling of the fire pump are:
The inlet medium of the fire pump is insufficient or the inlet pressure is not enough, or the inlet pipe of the fire pump is blocked, or the air in the fire pump cavity is not exhausted. When the fire pump is idling, the impeller has no contact or little contact with the medium, and the work cannot be effectively performed, and the liquid cannot be transported out normally. These are all useless work. Because there is no effective work, the load on the motor is very small, and the generated current is also very small. There will be no impact on the motor. The idling of the fire pump is indeed fatal to the pump. Idling fire pumps are easy to cavitation, causing damage to the pump body and overcurrent parts; rotor parts and pump body of idling fire pump will generate heat, no liquid cooling, and those narrow gaps (such as sealing rings) are easily bitten by the effect of thermal expansion and contraction; idling multistage fire pump without lubrication, the balance plate will soon be burned and damaged.

During the early warning and maintenance of fire pump idling, it is recommended to improve the design of fire pump:
1. Special processing, tempering and heat treatment of the shaft of the fire pump are used to improve the hardness, and the material with low flexibility is used to prevent large swings and idling when idling;
2. Deal with each gap position of the fire pump, expand it under the allowable conditions, to prevent biting;
3. Use mechanical seals and packing cavities that do not need to rely on liquid media for lubrication;
4. Choose enclosed self-lubricating bearings without oiling. 

Compared with other fire pumps, the volume of the horizontal self-priming fire pump chamber is increased, and there is a place where water can be stored. Before the self-priming fire pump works normally, the cavity must be filled with liquid. There is a period of self-priming before operation. During this period, the air is continuously discharged to the outside of the pump. This period of time is partly idling.
Set the idling induction system. The fire pump is monitored in real time through modern equipment. When the fire pump is idling, it immediately alarms and automatically stops to protect the safety of the pump set.