age please of Lennox

[Harry McBride]

Lennox compressor unit
Model# HS9-411-3P
Serial# 51

[mnahrgang]

A lot of the Lennox unit's I've seen have had a seperate date sticker. Look for that. Or look for a date on the same sticker.

This model/Serial # doesn't correspond with my notes on the dates found in them.

[Harry McBride]

No separate sticker. This data was imprinted on a metal data plate. Have never seen a two digit Serial#.

[Michael Larson]

Originally Posted by hmcbride

Lennox compressor unit
Model# HS9-411-3P
Serial# 51

According to a 1977 ARI book (the HS9 lived from 1976 to 1981)

[Russel Ray]

If it's a "51," I have no idea other than what Michael posted. If it's "S1," then it would be 1981.

Even if it's "51," it's probably really "S1"; typos at the manufacturing plant are not unheard of.

[Russell W. Meyers]

Harry,

Per Preston's 1960 2000 edition.
Lennox HS9-411-1P 1982 35,200 BTUH 7.8 EER
Lennox HS9-411-7P 1981 34,400 BTUH 7.6 EER