I guess that's why my control board edge connector had corrosion; no float switch to turn off the AC.This post saved me having to call for HVAC service. I checked the air handler in the attic, and the float switch had been tripped due to standing water in the pan below the air handler. I drained the water, and AC was back on in 10 mins. I'll have to check the outside drain line to find out why it was draining into the pan instead of the external drain, i'm guessing i have a clog somewhere. I guess any pvc safe drain un clogger would be fine to run down the drain line?
Glad this thread was the second google result for "themostat no power".