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Air Conditioning Problems

hot-worldHere in Vermont we have a fairly short season of hot and humid weather. Mostly we can get by rolling down our windows and letting fresh air in to keep us comfortable. But on those wicked hot days most of us really appreciate having the air condition working in our cars to keep us cool .

Trying to explain how the air conditioning system of your car works is not an easy task. This is because it’s fairly complicated and counter-intuitive.

Basically, when you push the A/C button in your car, you are starting a chain reaction that removes the heat from inside your vehicle and transfers that heat to the outside air. Once all the hot air and humidity has been removed the air becomes cooler. It can be a real ahhhhhhhhhhhh moment once the hot air is removed & you’re left with cool refreshing air .

Here is a more technical explanation of how your Air Conditioning works is from Edmunds.com:

There are six basic components in the A/C System: compressor, condenser, receiver-drier, expansion valve, the evaporator and the life-blood of the A/C system, the refrigerant.

air conditioning picture

Step One: The compressor is the power unit of the A/C system. It is powered by a drive belt connected to the engine’s crankshaft. When the A/C system is turned on, the compressor pumps out refrigerant vapor under high pressure and high heat to the condenser.

Step Two: The condenser is a device used to change the high-pressure refrigerant vapor to a liquid. It is mounted ahead of the engine’s radiator, and it looks very similar to a radiator with its parallel tubing and tiny cooling fins. If you look through the grille of a car and see what you think is a radiator, it is most likely the condenser. As the car moves, air flowing through the condenser removes heat from the refrigerant, changing it to a liquid state.

Step Three: Refrigerant moves to the receiver-drier . This is the storage tank for the liquid refrigerant. It also removes moisture from the refrigerant. Moisture in the system can freeze and then act similarly to cholesterol in the human blood stream, causing blockage .

Step Four: As the compressor continues to pressurize the system, liquid refrigerant under high pressure is circulated from the receiver-drier to the thermostatic expansion valve . The valve removes pressure from the liquid refrigerant so that it can expand and become refrigerant vapor in the evaporator .

Step Five: The evaporator is very similar to the condenser. It consists of tubes and fins and is usually mounted inside the passenger compartment. As the cold low-pressure refrigerant is released into the evaporator, it vaporizes and absorbs heat from the air in the passenger compartment. As the heat is absorbed, cool air will be available for the occupants of the vehicle. A blower fan inside the passenger compartment helps to distribute the cooler air.

Step Six: The heat-laden, low-pressure refrigerant vapor is then drawn into the compressor to start another refrigeration cycle

If your car has an A/C problem, it is pretty much one of two things: No cool air or insufficient cool air.

No Cool Air

  • Loose or broken drive belt
  • Inoperative compressor or slipping compressor clutch
  • Defective expansion valve
  • Clogged expansion valve, receiver-drier or liquid refrigerant line
  • Blown fuse
  • Leaking component: any of the parts listed above or one of the A/C lines, hoses or seals

Insufficient Cool Air

  • Low refrigerant charge
  • Loose drive belt
  • Slipping compressor clutch
  • Clogged condenser
  • Clogged evaporator
  • Slow leak in system
  • Partially clogged filter or expansion valve

I hope Edmunds.com’s explanation is helpful.

If your car’s air conditioning is not blowing cool enough or not at all, make an appointment with Auto Craftsmen and we will make it blow cold or figure out why it’s not working.

Call 223-2253 or email: [email protected]