Need help on the age:
m/n UGS105D11N-1A
s/n HM409295
Gary,
Borg Warner is owned by York.
If the serial number has 2 letters at the start than the 1st or 2nd letter is year of manufacture.
So…H=1978 and M=1982
It was manufactured 27-30 years ago.
AC or Furnace?
I’ve never seen a Borg Warner furnace.
It’s got to be a boiler.
Furnace
27 - 30 years old.
You have a choice: 1978, 1982, or 1999.
Probabilities after analyzing my own database:
1978 - 82%
1982 - 18%
1999 - 0%