I have an old Lennox furnace (circa late 60's) with an A/C added on. The schematic has not been marked up after an addition of the A/C. Had an air blower relay failure recently and noticed that A/C compressor still switched on, even without the blower running. That can't be right. When heat is used, the blower does not come on unitl the air is hot.
Can someone point me to a "typical" schematic for a Furnace-A/C system.