7–1 T-354SECTION 7SERVICENOTETo avoid damage to the earth's ozone layer, use a refrigerant recovery system whenever removingrefrigerant. When working with refrigerants, you must comply with all local government environmentallaws. In the U.S., refer to EPA section 608.WARNING!Never use air for leak testing. It has been determined that pressurized mixtures of refrigerantand air can undergo combustion when exposed to an ignition source.7.1 SECTION LAYOUTService procedures are provided herein beginning with refrigeration system service, then refrigeration system com-ponent service, electrical system service, temperature recorder service, and general service. Refer to the table ofcontents to locate specific topics.7.2 SERVICE VALVESThe compressor suction, compressor discharge, and liquid line service valves (see Figure 7.1) are provided with adouble seat and a gauge connection, which enables servicing of the compressor and refrigerant lines. Turning thevalve stem clockwise (all the way forward) will frontseat the valve to close off the suction, discharge or liquid lineand open the gauge port to the compressor or low side. Turning the valve stem counterclockwise (all the way out)will backseat the valve to open the connections and close off the port.With the valve stem midway between frontseat and backseat, the lines are open to both the connections and thegauge connection.For example, the valve stem is first fully backseated when connecting a manifold gauge to measure pressure.Then, the valve is opened 1/4 to 1/2-turn to measure the pressure.Figure 7.1 Service Valve1. Suction, Discharge or Liquid Line Connection2. Service Port3. Stem Cap4. Valve stem5. Compressor Or Filter Drier Inlet Connection- - - - -VALVEFRONTSEATED(Clockwise)VALVEBACKSEATED(Counterclockwise)12345
