I just had a new furnace installed (Lennox G71MPP) which is supposed to have variable stages, up to 60. However, after looking at the diagnostic code on the furnace, I've noticed only the following three codes appear at different various times:


I know the "H" stands for heat and the last three digits represent the CFM. However, my concern is that the unit is only running in stage 1 or stage 2.

After reading a very helpful older thread:

...I would think that I should see 2 digits between the H and A, representing the variable %.

For example, "H63A720" would mean the heat is running at 63%, right?

Since I am only seeing 1 digit after the H (either a "1" or "2"), is my furnace only running in two stage mode?

Also, the previous thread discussed checking the dip switches. I'm not sure how to find my dip switches. Any pointers?

If anyone else has a Lennox G71MPP that can verify how to determine if the furnace is running in true variable mode instead of two-stage mode, I'd greatly appreciate any tips.

Thanks so much!

My setup
Furnace = Lennox G71MPP
AC = Lennox XC13
Humidifier = Aprilaire 600a
Thermostat = Honeywell VisionPro 8000 (3H / 2C)