If you turned on your home's central air conditioner today, and there is a buzzing sound coming from your furnace but no cooled air is coming out of your vents, then the capacitor on the system's blower motor has likely failed. A capacitor is a small electrical part that holds a charge and is necessary to start your furnace's blower motor. When the capacitor gets too old and will no longer hold a charge, then the blower motor is not able to start running and will make a buzzing sound. Thankfully, a replacement capacitor is very inexpensive and something you can replace yourself even if you do not have any experience repairing HVAC system units.
Here are the steps you must follow to replace the capacitor for your furnace's blower motor to get your air conditioner blowing out cold air again.
Step 1: Turn Off the HVAC System's Power
Your home's HVAC system is hardwired into your home's power panel. In order to "unplug" the system from its electrical source, you need to turn off the breakers that service the system. Typically, residential HVAC systems will have two or three breakers dedicated to them. Turn off all of the breakers labeled for the HVAC system.
Step 2: Remove the Old Capacitor
The blower motor is the part of your furnace that is round and has a bladed circular part inside of it that turns. Stuck to the side of the blower motor is a cylindrical capacitor that has two wires connected to its top. The capacitor is about three inches long and about an inch in diameter. Pull the capacitor out of its holder and unplug each of the wires on its top.
Step 3: Get a New Capacitor
Take the capacitor that you removed to your local home-improvement store and purchase a replacement.
Step 4: Replace the Old Capacitor
Place the wires you removed from the old capacitor onto the new one. The connections are universal, and it does not matter which wire you connect to which post.
Step 5: Dust Your Furnace
While you have the door open and are working on your furnace, take a moment to replace its filter and dust off any surfaces where you see any dirt or dust buildup. You can use your vacuum cleaner to make the task easier.
Step 6: Turn On the HVAC System's Power
Finally, restore the power to your HVAC system by turning the breakers back on. Test the new capacitor by turning down your thermostat and checking to ensure that the air now flows from your system. If replacing the capacitor does not solve the problem, then you will need to have a service technician come to your home and conduct further troubleshooting.
Talk to a company such as Airwaves Heating & Air Inc for further advice or professional help.