Looking for info on Keeprite Condensing unit

Can anyone tell me the tonnage & age of this A/C (condensing) unit?

Manufacturer: Keeprite
Model: KSSC 28 01
Serial #: 9181262859



You will have better success contacting the manufacturer as refrigeration equipment is a little more difficult to understand their numbers. www.keepriterefrigeration.com Look for a number for Tech support and talk with them. They will be able to tell you the age and tonage.
Best regards,

The 1st digit is the year, and the 2nd and 3rd are the week of manufacture. This format applies to units from 1980 - 1994. So it would seem like the 18th week of 1989.