My furnace works like this: Burners come on, then blower comes on. They stay on until it makes my thermostat setting, say 74.
On some inspections, the furnace does this: the burners come on, then the blower, but after a few minutes the burners go off and the blower stays running. It continues this way until it reaches the set temp. This is on old furnaces.
My question is: Is this a case of “short cycling”, or on old furnaces is this the way they were designed to run?