Comfort-aire manufacture date

This furnace appeared to have two serial numbers.

AR3D106 F3690 0668


Can anyone help me determine the age of this unit?

Without looking it up, I’d guess that it is the 36th week of 1990.

Thanks Larry… that is the site that I always use however the situation with two serial numbers is a little different for me. Even using this information it is still not clear what the exact date is.

Did you get the ANSI date?

The age is usually within 3-4 years of

It was 88 so I’m going to go with 90 as an estimate and recommended an HVAC tech to further evaluate to determine the exact age when the unit is serviced. Thanks for trying, man!