a pressure sensor connected in {TAIL ~ line} with {HEAD ~ said distribution trunk tube} and adapted to sense and indicate normal and abnormal operating pressures; and 
a pressure sensor connected in { TAIL ~ line } with { HEAD ~ said distribution trunk tube } and adapted to sense and indicate normal and abnormal operating pressures ; and
OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH