My AC quits working on really hot days (+100 degrees). The thermostat just goes blank. After the sun goes down and the attic cools off (AC is in attic) the thermostat comes back on and the AC starts up. This happened for two days. The third day I turned the fan to "ON" and left it running throughout the day thinking the cooler house air would keep everything in the cabinet cool. AC worked fine for two more days. Next day my son turned the fan to "AUTO" in the morning. When I got home that evening after another +100 days the thermostat was blank again, no AC. Sun when down, AC comes back on. Next day in the morning turned fan to "ON" and AC has been running fine since. I'm afraid to turn the fan off. I'm thinking some sort of temperature issue with the circuit board maybe. Appreciate any help.

Looked up XB80, its says the xb80 is a furnace,I wondered why an ac was in the attic,
Chances are the blower in furnace is getting hot and stops working for some reason
When this happens go outside and check the ac is it working OK?