I couldn’t find the year of this furnace by what has been posted here , unless I’m not seeing it right. I’m thinking it’s only several years old as the owners manual for the a/c unit acompanying it has written 4-23-03 on it. Would the first number be the year made??
That one looks to be manufactured by someone else for York, probably during high demand, plant shut down, natural disaster, etc. It looks to be September 2002, and since it’s a fairly large unit, at 3½-tons, it would not be unusual for it to have sat in the warehouse until April 2003 when it was installed, especially if a smaller manufacturer built it for York, or took one of their units and sold it to York during one of the aforementioned events.
CD5AXA042021AAAA Looks more like a Carrier Evaporator Cased Coil number.
C= coil D= piston cased coil 5= upflow/downflow A= major series change X= position not used A= Standard 042 = 3 1/2 ton 021 = 21inch casing width AAAA unknown it was not listed on the pdf file from Carrier.
Did you get this number outside the furnace or inside the furnace? Newer York furnace numbers usually start P1 or P2