A control unit controls either the inflow liquid pump only or both the inflow liquid pump and the outflow device depending on {HEAD ~ an inflow irrigation liquid pressure} from {TAIL ~ a pressure sensor}  
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A control unit controls either the inflow liquid pump only or both the inflow liquid pump and the outflow device depending on { HEAD ~ an inflow irrigation liquid pressure } from { TAIL ~ a pressure sensor }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH