NATE Air Conditioning and Heat Pumps Practice Exam

The correct answer is based on the standard acceptable tolerance for capacitance values in run capacitors. Run capacitors are typically designed to operate within a specific microfarad rating that is printed on their casing. The acceptable capacitance reading is defined as being within a range that accounts for manufacturing variations and the aging of the capacitor over time.

When you say "plus or minus 10% of" the microfarad rating, it indicates that the capacitance can vary both above and below the stated value by a margin of 10 percent. This is significant because it ensures the capacitor is functioning properly within the expected parameters, which is crucial for the efficient operation of the air conditioning or heat pump system. If the capacitance deviates more than this range, it could lead to poor performance or potential failure of the component.

Typically, allowances greater than 10% may not be acceptable for run capacitors, as they could indicate a failure or degraded performance that could affect the entire system's efficiency. Hence, understanding and applying this tolerance is essential for technicians when diagnosing or servicing HVAC equipment.