1. There is positive water flow in the spray pipe;
2. The water flow indicator has a mechanical failure and cannot return to its position automatically;
3. The output terminals of the water flow indicator are normally open and normally closed, and they are connected to the normally closed by mistake;
4. The input wire of the water flow indicator module is short-circuited;
5. In this loop, there may be other equipment addresses that are the same as the address of the water flow indicator module.
