Copyright Goodheart-Willcox Co., Inc. 812 Air-Conditioning Systems Condensing (Outdoor) Unit 1. Record the outdoor air temperature. 2. Check the ground surrounding the condensing unit for signs of erosion. Clear away any plants, shrubs, and branches from the outdoor unit so there will be good airflow across the condenser coil. 3. Inspect disconnect box, compressor and condenser fan motor capacitors, contactors, relays, circuit boards, electrical connections, and equipment grounding. Look for any signs of burning, damage, or wear. 4. Record the compressor amp draw and the condenser fan motor amp draw. 5. Inspect the refrigerant lines and connections for damaged insulation, signs of leaks, or other damage. 6. Record suction and discharge pressures. 7. De-energize the unit at the disconnect box (test to ensure that no voltage is present) and clean the condenser coil. The condenser should be blown clean of debris. Any bent fins should be straightened. A carbon dioxide blower or vacuum cleaner can be used to clean the unit. Pressurized washing wands are useful to clean the coils from the inside out, Figure 32-22. Clean the fan blades if needed. Air Handler (Indoor Unit) 1. Clean or replace the air filter. 2. Inspect disconnect box, indoor fan motor capacitor, contactors, relays, circuit boards, electrical connections, and equipment grounding. Look for any signs of burning, damage, or wear. 3. Record the blower motor amp draw. 4. Record static pressure and ΔT across the evaporator. Compare measurements to manufacturer’s target. 5. De-energize the unit at the disconnect box (test to ensure that no voltage is present) and clean the evaporator coil. 6. Inspect condensate pan and drain for biological growth. Clean pan, drain, and condensate trap and piping. Condensate that escapes the drain pan may drip on the furnace heat exchanger, corroding (rusting) it. If the condensate drain is clogged, it may be possible to blow out the blockage using compressed gas, Figure 32-23. Place algaecide tablets in the pan. See Figure 32-24. Dirty Coils Decrease Efficiency Dirt on evaporator and condenser coils decreases the coil’s ability to transfer heat and, in extreme cases, increases resistance to airflow across the coil. To keep the system operating at maximum efficiency, the coils should be cleaned regularly. Thinking Green SpeedClean Figure 32-22. This technician is using a pressurized mix of chemicals and water flowing outward through the condenser coils. DiversiTech Corporation Figure 32-23. This drain cleaning gun blows away drain blockages using dry, compressed carbon dioxide.