The grain dryer 10 further includes a heating unit 40 which is operable to draw {TAIL ~ ambient air} from the environment, heat the ambient air, and advance {HEAD ~ the heated air} into the plenum chamber 28 
The grain dryer 10 further includes a heating unit 40 which is operable to draw { TAIL ~ ambient air } from the environment , heat the ambient air , and advance { HEAD ~ the heated air } into the plenum chamber 28
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH