What to Check During an AC Maintenance Tune-Up: Capacitor to Drain Line

Outside, we check the amp draw on the condenser fan motor and the compressor, then measure the power factor. A power factor below 0.94 is an early sign of a weak capacitor. After the power is disconnected and confirmed off, both sides of the dual run capacitor are tested against their rated µF, using a 10% tolerance to decide whether it’s still in range.

With the system running, we take noninvasive readings with measureQuick to confirm performance on a 3-ton system without gauging up. The readings include suction and liquid line temperatures, return and supply dry bulb and dew point, a 20.5°F temperature split, and airflow. If everything reads in the green, there’s no need to connect gauges.

Inside, the maintenance continues with:

• Testing the float switch
• Inspecting the blower wheel and evaporator coil
• Checking the PVC drain line for sags that can create a double trap
• Flushing the drain line until the water in the vacuum runs clear, then priming the trap
• Pushing insulation back off the panel so it doesn’t sweat when it reaches dew point

Every tech runs a tune-up a little differently. This is one field-proven process for catching problems early and preventing callbacks.