I have a Carrier Infinity system - full system (heating and air conditioning) newly installed a little over a year ago (southern Ontario, Canada).
I have programmed the system for continuous fan operation - the furnace fan should always be running at some modest speed. When new, it worked as expected - fan speed ramps up or down between continuous fan speed and heating or cooling speed (depending on season/mode).
During the current cooling season, I have recently noticed a different behavior. The furnace fan sometimes shuts off completely along with the A/C compressor, until the A/C cycles on again. This is intermittent because the fan sometimes does just ramp down to its "continuous" programmed speed as I expect it to.
Is the system intermittently shutting down because it detected a problem? If so, what might the problem be? Could it be icing up? Is this what the system is supposed to do if it detects what could be icing condition (evaporator temperature/pressure too low)? Is this a fault requiring a service call?