Blower doesn't kick into high speed when there is a call for cooling. The airflow isn't sufficient, resulting in unbalanced temps between floors. Heat runs at the lowest speed, continuous fan is slightly higher, and cooling runs at the same speed.
The A/C is a 2-ton, blower is a Q2 - so I can only assume that it should be on high.
I read something about the cooling fan relay going bad on Lennox control boards on this particular model. If that is the case, would moving continuous fan to the high speed tap to get proper airflow pose a problem? (instead of getting the board replaced -> will not attempt to myself) The t-stat closes the circuit between G and R (in addition to R + Y) during a call for cooling anyway - practically equivalent to calling for continuous fan.
I won't touch it unless it's something as simple as changing a DIP switch/jumper setting. Posting this more out of interest.
Mod(s) - feel free to delete this if it's too close to asking a direct DIY question)