Capacitors are electrical components used in certain Genuine Comfort PTAC units to support the operation of fan motors and compressors. Understanding their purpose and electrical ratings can help identify potential causes of equipment starting or operating issues.
What Is the Purpose of a Capacitor?
A capacitor stores electrical energy and helps create the electrical conditions needed for certain motors and compressors to start or operate efficiently.
Depending on the unit's design, capacitors may be used for:
- Indoor fan motors: Support the operation of the fan that circulates air throughout the room.
- Outdoor fan motors: Support the operation of the fan that moves air across the outdoor coil.
- Compressors: Support the starting and/or running of the compressor, which circulates refrigerant through the system.
Not every unit uses separate capacitors for each component. Capacitor configurations vary depending on the model and motor design.
Understanding Capacitor Ratings
Capacitors are identified by two important electrical ratings:
Microfarads (µF or MFD): Measure the capacitance of the component. The replacement capacitor must have the capacitance specified for the applicable motor or compressor.
Voltage (VAC): Indicates the capacitor's rated AC operating voltage. A replacement capacitor must have an appropriate voltage rating for the application.
Important: Capacitors must be selected according to the equipment manufacturer's specifications. Using an incorrect capacitor can cause equipment malfunction or component damage.
Compressor Capacitors
Some compressors use capacitors to assist with starting and/or running during operation.
A faulty compressor capacitor may prevent the compressor from starting correctly, even when other components appear to be operating.
Example of a compressor capacitor.
The capacitance (µF/MFD) and voltage (VAC) ratings are identified on the capacitor label.
Fan Motor Capacitors
Certain indoor and outdoor fan motors use capacitors to support normal motor operation.
A faulty fan motor capacitor may cause the fan to fail to start, operate intermittently, or experience difficulty running.
Example of a fan motor capacitor rated at 1.5 µF and 450 VAC.
How to Identify the Correct Capacitor
The required capacitor specifications may be printed directly on the motor's identification label or listed in the applicable equipment documentation.
For example, the motor shown below specifies a 1.5 µF / 450 V capacitor.
Always verify the required capacitor specifications for the exact unit and component before selecting a replacement.
Example of a fan motor identification label showing the required capacitor rating of 1.5 µF / 450 V.
Common Signs of a Potential Capacitor Issue
A faulty capacitor may contribute to symptoms such as:
- The indoor or outdoor fan failing to start.
- The compressor attempting to start but not running.
- A motor humming without starting.
- Intermittent motor or compressor operation.
These symptoms can also be caused by electrical supply problems, wiring issues, motor failures, control board faults, or other equipment conditions. A capacitor should not be assumed to be defective based on symptoms alone.
Important Electrical Safety Information
Warning: Capacitors can retain a dangerous electrical charge even after the unit has been disconnected from power.
Capacitor testing, discharge, and replacement should only be performed by qualified service technicians using appropriate procedures and equipment.
Do not attempt to replace a capacitor without confirming the correct specifications and identifying the underlying cause of the equipment issue.
Need Assistance?
If your Genuine Comfort unit is experiencing a fan or compressor starting issue, contact Genuine Comfort Support with your unit's model number, serial number, and a description of the symptoms.
Our team can help determine the appropriate troubleshooting steps and identify the correct replacement components when required.