Air is forced through {TAIL ~ the tube bundle} by either a draft induction blower located at the outlet end of {HEAD ~ the tube bundle} or a forced draft blower located at the inlet 
Air is forced through { TAIL ~ the tube bundle } by either a draft induction blower located at the outlet end of { HEAD ~ the tube bundle } or a forced draft blower located at the inlet
OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH