Bay fire equipment in the wet alarm valve on the signal butterfly valve and pressure switch connected to the two signal lines, why there are two lines and intermediate relay
New national standard requirements: must pressure switch forced start + fire linkage double insurance
It may be 24v bar, pressure switch action in addition to the alarm after the host signal, but also have to start the spray pump. Your relay should play the role of conversion it. Pressure switch action after the start of the relay, a group of normally open point to the input module, another group of open pump
Two lines are feedback line relay is short circuit caused by external lines paralyzed
