Figure 1. Indoor airflow system evaluation results.

This troubleshooting situation centers around an older 3-ton split comfort cooling system, and the customer is calling because their home is “just not comfortable.” The homeowner also tells the dispatcher that while the unit is operating and air is coming out of the registers, the temperature in the house is too warm, and the system seems to be running constantly. The homeowner also mentions that they replaced the filter, but it didn’t seem to make any difference.

When you arrive, you confirm that the air handler is running, and although the thermostat setpoint is 75°F, the indoor temperature is too warm. Moving to the outdoor unit, you find that the compressor and outdoor fan motor are operating normally, and that the condenser coil is clean. When you confirm the outdoor ambient temperature and check the suction and discharge pressures of the system, you get the results shown in Figure 1.