Lennox compressor unit
Model# HS9-411-3P
Serial# 51
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.
No separate sticker. This data was imprinted on a metal data plate. Have never seen a two digit Serial#.
According to a 1977 ARI book (the HS9 lived from 1976 to 1981)
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.
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