Heil heater age?

Serial number H350 91133, older Heil unit, any ideas on the age?

This looks like what you have Jeff. 1983

**Heil-Quaker – (1980 thru 1989) **
Serial Number format: H55116328
(This serial number is from actual air-conditioning unit).

[size=2]Date of Manufacture: Using the first and second digits of the serial number H55116328 you will find the year of manufacture. The first digit (Always the letter “H” for the 1980’s) is the decade of manufacture and the second digit is the individual year of the decade. This unit was manufactured in 1985. [/size]

http://hisearch.org/Heil.aspx

Makes sense, the A/C looks as old and the tag was shot thanks