Your central air conditioner is called a split-system unit because one part sits outside your home and the other rests inside your home within the furnace unit. These parts are called the condensing unit and the air handler, respectively. Each part has its own motorized fan that provides vital functions for the cooling process. If either fan were to experience troubles or break, your home's indoor temperatures could suffer.
Here are a couple of HVAC problems that can occur due to a broken fan and leave you without cold air. Call an air conditioning repairs tech for assistance.
Overheating Condensing Unit
The condensing unit's function starts when the thermostat inside your home signals the compressor to compress the gas refrigerant sitting inside that part of the system. The compressed refrigerant then travels into the condensing coils, where the gas is altered into a liquid that can more easily travel into the house to the air handler. This phase change causes the coils to become hot on the surface, which isn't a problem because the nearby fan circulates air across the coil surface and prevents overheating.
If the fan slows down considerably or stops, the condenser coils can become overheated and trip a safety mechanism that shuts down the entire unit. The safety will keep tripping every time you try to run the unit without an operable fan.
Turn the unit back on and listen until it does trip off again. Did you hear the sound of the fan? Did it sound as fast as normal? If the fan sounds slower, or you didn't hear the fan at all, you should call in an HVAC technician to check the fan and replace the parts as needed.
Lack of Circulating Cold Air
The liquid refrigerant travels from the condenser coils, through a copper lineset, and into the air handler and the evaporator coils inside. The evaporator coils change the liquid back into a gas and accordingly become cold on the surface. A fan near these coils circulates air but to cool the air rather than warm the coils. This cooled air then passes out into your home to lower your indoor temperature.
If the fan near the evaporator coils breaks, you won't have any cold air coming out of your vents. You won't have any air coming out at all, which can help rule out some problems that would cause a warm air return. You should call an HVAC tech, like one from Mr. Reliable Plumbing & Heating, as soon as you stop getting any cold air out of the returns so that your home can get back to a cooler temperature faster.