Copyright Goodheart-Willcox Co., Inc. 824 Air-Conditioning Systems 32.6.3 Ductless System Maintenance Much of the scheduled maintenance performed on ductless systems is similar to that performed on central air-condi- tioning systems, such as inspecting the system and cleaning the condenser coil. But there are differences as well. Always refer to and follow the maintenance guidelines provided by the manufacturer. Maintenance procedures will vary from product to product, so be sure to check. Maintenance of indoor units takes place in living spaces. Therefore, making sure the room stays clean is critical. Use drop clothes or tarps to cover furnishings and flooring. Wear shoe covers so you do not track dirt into the house. Remove and clean the air filters in the indoor units. See Figure 32-41. If a filter is damaged or worn, replace it. A common maintenance task is cleaning or replacing the air filters in the indoor units. Biological material including mold can grow in conden- sate pan, on the coil surface, on blower wheel blades, and elsewhere inside the indoor unit. To prevent microorgan- isms from forming in an indoor unit, add biocide tablets to the condensate pan. These are designed to prevent the Fujitsu General America, Inc. Figure 32-41. This technician is examining an air filter from an indoor unit. 32E: Residential Central Air-Conditioning: No Cooling Overview The owner of an 1800 ft2 residence, Ms. Washington, has reported that her split central air-conditioning system is not providing cooling. Upon arriving at the residence, the technician, Maria, identifies herself and verifies that Ms. Washington requested service. Before entering the residence, Maria puts on shoe covers. Customer Interview Ms. Washington explains that the air-conditioning system has been blowing hot air for the past two days. “I don’t get it. It’s over 80°F in here. I set the temperature for 75°F, but it’s blowing hot air! Do I need a new system?” Maria asks questions to learn that Ms. Washington noticed the problem the previous day and that the system had been operating fine. Maria also learns that no repair work has been needed for the system in the past few years. Initial Inspection Maria begins by inspecting the thermostat. It is calling for cooling and set to 75°F, and the current temperature is 82°F. Maria inspects the indoor unit and finds that the blower is running and the air filter appears clean. She inspects the interior of the air handler and sees nothing that indicates a problem. The ductwork looks fine and there are no signs of leaks on the refrigerant tubing. Maria inspects the outdoor unit. The outdoor unit is quiet. Neither the compressor nor the condenser fan are running. System Testing Maria measures 240 V at the disconnect and then measures 240 V on the line side of the contactor. Wearing gloves and using a nonconductive tool handle, Maria presses in the contactor’s contacts, and the compressor and condenser fan start and run as they should. When Maria releases the contactor’s contacts, the compressor and condenser fan turn off. Analyze and Discuss 1. Based on the information provided and the ladder diagram from Service Call Troubleshooting 32D, what are some possible causes of the problem? 2. If neither the compressor nor the condensing fan started when Maria manually closed the contactor, what should she consider as potential problems? 3. Select one of the possible causes you identified in Question 1 and describe the procedure for repairing the issue. 4. After completing the repair described in Question 3, how would Maria check to ensure that the repair was done correctly? How would Maria check the system to ensure that the repair solved the original problem? Service Call Troubleshooting