In the second operational position, the second register provides for {HEAD ~ residential used air intake} in the second chamber and expulsion of the air leaving this second chamber into {TAIL ~ the atmosphere} 
In the second operational position , the second register provides for { HEAD ~ residential used air intake } in the second chamber and expulsion of the air leaving this second chamber into { TAIL ~ the atmosphere }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL