Copyright Goodheart-Willcox Co., Inc. Chapter 32 Residential Split Air-Conditioning Systems 825 10 formation of slime, algae, mold, and other common con- taminants, Figure 32-42. Clean the inside of the unit thoroughly. If the unit is equipped with a condensate pump, clean the pump as well. It may be easier and neater to remove the drain pan and conden- sate pump and move them to another location to be cleaned. Evaporator coils in indoor units also need to be cleaned. To do this, remove outer panels, air filters, and any other accessories that could block the flow of cleaning fluid. Set up a large plastic bag or bib to catch and contain the cleaning fluid. This can be directed into a bucket for later draining, Figure 32-43. Biocide tablets RectorSeal Figure 32-42. Adding biocide tablets to an indoor unit’s condensate pan is often included as part of the unit’s maintenance. 32F: Residential Central Air-Conditioning: Poor Cooling Overview Continuing from Service Call Troubleshooting 32C, Mr. Gonzalez’s split central air-conditioning system is not cooling sufficiently. The technician, Sharon, has interviewed Mr. Gonzalez and inspected the system, but neither activity has suggested any specific potential causes. Sharon now begins measuring some system performance values. System Testing Sharon attaches a gauge manifold to the service valves at the condensing unit and measures suction pressure and discharge pressure. She takes temperature measurements of the suction line and the liquid line and calculates superheat and subcooling. She also measures the amp draw of the compressor. She compares these values to the design values provided by the manufacturer for the equipment. She finds: • Suction pressure is low. • Discharge pressure is low. • Superheat is high. • Subcooling is low. • Compressor amp draw is low. Analyze and Discuss 1. Based on the information provided, what are some possible causes of the problem? 2. Select one of the possible causes you identified in Question 1 and describe the procedure for repairing the issue. 3. After completing the repair described in Question 2, how would Sharon check to ensure that the repair was done correctly? How would Sharon check the system to ensure that the repair solved the original problem? Service Call Troubleshooting SpeedClean Figure 32-43. Use a pressurized washer with a plastic bib and bucket while cleaning an indoor unit’s evaporator.