The system also includes {TAIL ~ a pressure differential switch} which senses a drop in pressure across {HEAD ~ a pedal valve} 
The system also includes { TAIL ~ a pressure differential switch } which senses a drop in pressure across { HEAD ~ a pedal valve }
OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD