When a sensor detects {HEAD ~ a significant change} in {TAIL ~ air flow} and air pressure, a detection signal is analyzed by a controller unit microprocessor for comparisons with a preselected operating range for air flow and pressure 
When a sensor detects { HEAD ~ a significant change } in { TAIL ~ air flow } and air pressure , a detection signal is analyzed by a controller unit microprocessor for comparisons with a preselected operating range for air flow and pressure
OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH