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