We have a Carrier Heat & Air system with a Carrier Comfort Series Thermostat. The thermostat is set on heat at 65 degrees. We noticed this morning it was blinking heat/on on the bottom right corner. I turned it off, went in the attic to feel if the unit was hot ( we had a motor unit go out once and almost caught the house on fire). It was fine. Turned the heater back on & it no longer blinked. Why? Does it have anything to do with the running cycle? My husband is upping the temp all the time. He said he didn't so not sure what may have happened.

Many thermostats have a minimum off time between cycles (usually 5 minutes). If the thermostat was satisfied then, in less than the minimum off time, were turned up, it is likely it would blink until the minimum off time had elapsed, after which the heat would come on & the stat would quit blinking.