I'm assuming that you have it in heating mode and that it is a gas fired furnace. There is a fan that exhausts combustion air out of the combustion chamber. It runs for a few minutes after the burner turns off in order to exhaust remaining gases. The timer unit may be malfunctioning on this feature.
It means that the unit is low in freon and the line temperature is to low.
It will not work right.
either a relay is bad or you have the switch turn to man on thermostat
Have you checked the breaker outside by the unit
Central Unit ended in 2011.
Central processioning unit.
central processing unit
Central Processing Unit .
Central Processing Unit
Central Processing Unit.
Central Processor Unit --> CPU
In general when speaking of computer hardware it is the CPU (central processing unit) also called the processor. As a whole unit though, it is a combination of the CPU, the Motherboard, RAM, and the operating system.