Copyright Goodheart-Willcox Co., Inc. Chapter 32 Residential Split Air-Conditioning Systems 811 10 The gasket that joins the quick-connect fittings should be covered with clean, dry refrigerant lubricant just before assembly. When tightening quick-connect fittings, avoid applying excessive pressure to the wrench. Excessive pressure may distort the fitting and cause it to leak. Two wrenches should be used to tighten the fitting to prevent the tubing from twisting, Figure 32-21. Some quick-con- nect fittings can be resealed several times with the use of a special tool. 32.5 Servicing Central Air- Conditioning Systems For residential air-conditioning systems, service generally falls into three categories: • Scheduled periodic maintenance. Scheduled maintenance is normally performed annually on residential air- conditioning systems, preferably before the start of the cooling season. Scheduled maintenance consists of inspecting and cleaning to ensure proper operation. • Unexpected problems. Unexpected problems occur when the owner notices that the system is not operating properly and contacts the service provider to schedule a service call. • System replacement or expansion. This type of service involves adding to an existing air- conditioning system or replacing parts of existing system with new equipment. 32.5.1 Scheduled Periodic Maintenance The purpose of an annual inspection and cleaning is to ensure that the system is ready for the upcoming cooling season. The service includes a visual inspection and mea- surements to identify potential problems. Each HVACR service company has a procedure for annual air-conditioning system maintenance. The following is a list of items generally included in the procedure: General 1. Refer to the manufacturer’s annual maintenance list for the specific equipment in the air-conditioning system. Note any item not included in your company’s general checklist. 2. If you have access to previous service records for the residence, compare the measurements from the previous maintenance with the current measurements. In Residence 1. Record thermostat type (nonprogrammable, programmable), mode setting, and temperature setting. Record indoor wet-bulb temperature, dry- bulb temperature, and relative humidity. 2. Inspect the duct registers, note if registers are fully open, partially open, or closed. Note if any registers are blocked by furnishings or other items. On suction line, connect coupling on end with elbow to evaporator coil Liquid line Service port Connect end of line with service port to condenser York International Corporation, Unitary Products Group Figure 32-20. Liquid line equipped with quick-connect fittings. The service port is used for making gauge manifold high-side pressure connections. Back up Tighten Wrench A Wrench B C Aeroquip Corporation Figure 32-21. Correct way to tighten a quick-connect coupling. Wrench A is held firmly while wrench B is turned. Note that the sleeve closest to the wall turns, but the sleeve on tubing C does not.