There are some lesser-discussed components to your central air conditioner that need just as much attention during maintenance and repairs as the condenser and evaporator themselves. It is helpful to learn about these parts so that you can perform some maintenance tasks on your own before you call HVAC services to handle larger jobs. Here are some of those lesser-known components, information about them and where to find them, and how you or your HVAC contractor can provide services for these parts.


Most central air conditioning units have an electrical cable box outside, but if you swing open the door on that box, you will see a pull switch. If you pull the switch and then turn it around, you will see two, piston-like pieces snapped into place. These are HVAC fuses, and they provide the jolt of power your unit needs to run. Your HVAC contractor can test these fuses to make sure they are still operational. If they are defunct and not emitting an electrical pulse when tested, your contractor can replace them with new and fresh fuses. If you want to test the fuses yourself, you will need a volt meter. The fuses may be purchased through a hardware or specialty store, or through your HVAC contractor.

Wiring into the Furnace

Considering the fact that a furnace blows hot and the air conditioner blows cold, you might find it interesting and invaluable to know that some of the electrical wiring from the air conditioner connects to the furnace. The furnace's blower is responsible for moving the cold air up and circulating it through your home. The wiring from the air conditioner activates the blower's engine and both the blower and the air conditioner are engaged and activated by the thermostat, which is connected to the same electrical panel inside your furnace. When your furnace or air conditioner are not functioning as they should, the contractor checks the panel in the furnace first, then the thermostat, and then the remaining electrical connections to find the source of the problem. (You can look for loose wires and loose connections, but be sure not to touch them. Point them out to your contractor instead.)

The Additional "Kill Switch" in Your Home's Electrical Box

The central air conditioner that has its own fuse box is connected not only to the furance and the thermostat, but also to your home's main electrical box. If the fuse switches in your electrical box are not clearly marked, it may take you some time to figure out which one of these switches is the "kill switch" for the air conditioner. (When your contractor provides repairs of any kind to your A/C unit, he or she will usually flip the switch in your electrical box as well as the outdoor fuse switch.) If you find that your air conditioner frequently blows the switch in the electrical box, you may need to check the A/C's fuses for the correct voltage and/or amps. This could indicate a problem with the fuses, or it could indicate a much larger problem that only your contractor can fix. To find out more, speak with someone like Metro Air.