I believe 85 is the lowest setting but I have had not a problem with it. My equipment is in a closet and the fans never come on as it does not get that hot. Unit has a manual override to run the fans without using the thermostat. Since I do not post enough the forum will not let me post a url...
Middle Atlantic Products makes a thermostat that you can plug your fan in to. The thermostat setting is adjustable starting at 85 degrees. Once temperature setting is reached the fan is turned on. Will run until the temperature drops below the set amount.