The three terminals of the fire pressure switch are not a common point, a normally open point, a normally closed point, the specific how to pick up the pump, how and fire linkage
You said which is the multi-line module, generally do not linkage, if you want to link in the host above the preparation of procedures
The description of the pressure switch is correct, then open the point, with the input module to take the signal, through the fire mainframe linkage start the spray pump.
Pressure switch, relay and input module and pump control cabinet to form a switch circuit.
