In this month’s troubleshooting problem, we have a customer who can only tell us that the equipment that serves their small office “isn’t working.” When you arrive, you confirm that the building temperature is far from the thermostat set point even though the indoor fan motor is operating normally and the return air filter is clean. Satisfied that the problem is not with the indoor section of the equipment, you move to the outdoor section. Noting the schematic diagram (click here for a PDF of the diagram), you use it to become familiar with the components and circuitry there.
When you evaluate the situation, you find the following: