Look for a sticker or tag that gives a date when the furnace was last serviced.Īlso Know, are Armstrong furnaces any good? The A931A furnace by Armstrong is a reliable, moderately efficient, economical option. A serial number starting with 0193, for example, may have been made the first week of 1993. The first two digits can be the week of the year that the unit was manufactured, with the third and fourth number indicating the year.
Also to know is, how do I find out how old my furnace is?
