One of the major components to the heating system is the blower. Once the air has been heated, the blower motor will kick on and begin circulating all of the warm air throughout the home. The blower has a motor that uses electrical components to turn the blower on when the time is right. The electrical component that turns the blower on and off is the capacitor. If a problem occurs with the capacitor, the blower will not operate properly, causing the home to remain uncomfortable. Hal Mechanical will share some of the common signs of a failed blower motor capacitor.
Signs of a Bad or Failing HVAC Capacitor
Clicking Noises – When a capacitor begins to develop problems one of the first symptoms you may notice is a clicking noise. That clicking noise occurs when the furnace tries to start up and the relay system will send power to the blower motor. If you hear that clicking noise and the blower fails to start up, turn the furnace off and have an HVAC technician inspect the capacitors and possibly replace them.
Electrical Burning Odor – When the furnace develops a sudden burning like odor or an acrid burning smell, that can indicate that the capacitor may be burned out. The electrical wiring that connects all of the electrical components such as the capacitor may have also overheated and burned. When you notice an electrical burn odor coming from your air ducts, that is most likely the furnace and potentially the capacitor or other electrical component has burned up. Again turn off the furnace until the furnace is repaired.
Blower Runs Erratically – If you notice some odd behavior from your blower, that is often a sign of a failing capacitor. When the blower tries to run and stop or appears to struggle to stay on, the capacitor may be having a hard time supplying a constant flow of power to the motor. Depending on the type and or age of the blower motor, some might have two different capacitors. One capacitor supplies power to start the motor, and a second motor to keep the motor running. If the motor has erratic behavior this most often points to a bad capacitor that needs to be replaced.
No Power to Blower Motor – When the capacitor to the blower motor has gone bad, burned out or is broken, it will not be able to relay power to the motor. As a result, the motor will not turn on at all. When the furnace fails to start or if it stops running when the blower is timed to start, this is a sign the capacitor has failed. There is no point running your furnace until the capacitor is replaced.
Blower Makes a Humming Noise – When the starter capacitor, the capacitor that start the blower cannot send the needed burst of power you may hear a humming noise. Another cause for a humming noise is when the capacitor is stuck. Sometimes, the capacitor’s internal mechanism can become stuck and not be able to stop sending power. A humming noise can also be early warning signs that the capacitors are wearing down. A humming noise can point to different problem but all point to the capacitor.