Stat finally gets satisfied when the sun starts to drop off (7 pm ). I have cathedral ceilings (15'-6")in living room, din room & east exposure.
The house Is about 50 years old. Living room& din room is apprx 450 sq ft and I'm dumping in about 750 cfm's. supply wall grilles(3) are at 9'-0 & return is a sidewall about 11'-0 center line(16 x 30 ). I also have a 30 x14 return ceiling grille in the center hallway on a 8'-0 ceiling. House floor plan is about 1100 sq ft. Why does this unit keep running during these high heat days ? I was thinking is it the cathedral ceilings with very old insulation?