Was wondering if anyone has the age of this Bryant forced-air gas furnace? Model# 80-393 U Serial# 36S 99193
Is this an older unit?
Recently the first four numbers in the serial number represent the week and year. Prior to that, it was complex in a series of letters and single digits. Try 905-672-0860 if stuck. 
September 1965.
Harry,
I have seen some old ones around here but that is the oldest so far:D
Happy inspecting
Hey, Bruce.
I get a lot of 1960s on, but [this babe here is my oldest](http://www.abouthomes.info/pics/Furnace octopus.jpg). It had the manufacturer plate still on it, 1938, which is when the wise ol’ granddad built his house. To see such an octopus was a pleasant experience. And it was still working. Note the modern insulation upgrade on the air ducts! My wise ol’ grandmother would have been proud: “Just wrap some aluminum foil around it!”
IT WOULD BE NICE IF THEY COULD JUST PRINT THE YEAR!!! on ALL FURNACES…
They have mechanical engineers that design them, however they are not smart enough to “state” a year in plain view…It would be nice to see without have to be a cryptologist!
0234508234098pdflkhs35n-085-8325-89-028345klnlkshrfo9ua09u4930hb54 - The codes get really old…
I feel the same frustration at times, the more you inspect the easier it gets…
Thanks, Russell! Bruce, I see these all the time. Especially in flips. See the flippers don’t want to replace the HVAC system with a new 13 SEER system. It is just easier to see if the property inspector will call them on it.