The furnace warms the home by heating air and blowing it through the ducts and vents and back into the house. That said, one component malfunctions, you might have an entire system that doesn't work as it should. For example, the capacitor is one of the more complex parts of the system that often experiences issues. Here are some ways to tell when your capacitor has problems and possible solutions.
Rapid on and Off Cycles
When the capacitor malfunctions, the furnace will turn on, but it might quickly overheat. You should know that overheating can cause fires and further heater damage. As such, the system has a limit switch that shuts it off automatically if it overheats. Ultimately, this prevents quick cycling between the system's on and off states. As such, have an HVAC service technician take a look to avoid further heating damage and the expensive power costs that might result from short cycles.
An Incessant Hum from the System
Note that this crucial part of the system enables the current to reach the fan motor of the heater, which allows the fan to start. So, strange, low buzzing sounds may accompany the initial ignition of your unit if the part is failing. Moreover, air may begin to blow from the heater vents after a brief period of the hum. On other occasions, the sound may persist, and the heater may fail to turn on, indicating capacitor failure.
A Malfunctioned or Damaged Capacitor
A complete absence of heat could also indicate a faulty capacitor. This is usually the case when your heating system does not ignite. If you notice this issue, you can try increasing the temperature to gauge whether the system will start heating. More importantly, it is crucial to examine the likelihood of a broken heater capacitor, as this is one of the parts that lead to a complete inability to heat.
A Click with No Heat
If your heater is operational, you should hear a single-click noise as it powers up. However, if you have capacitor issues, instead of the heater running, you might get a series of clicks. The sound could last several minutes before it stops working, or it might occur only once or twice. If your capacitor keeps clicking, it is time to call an expert for help. They will troubleshoot and find the trouble with the system and the ideal solution.
These are the most common indicators that your capacitor has failed or is malfunctioning. Consulting a local HVAC service technician will help troubleshoot and solve the problem to restore heating.