There is disclosed {HEAD ~ a furnace} having {TAIL ~ an air flow path} for heated air and combustion products that passes through a condensing heat exchanger 
having
There is disclosed { HEAD ~ a furnace } having { TAIL ~ an air flow path } for heated air and combustion products that passes through a condensing heat exchanger
OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH