Carrier 69NT40-541-505 Operation And Service Manual

T-368 7–2Figure 7.2 R-134a Manifold Gauge/Hose Set1. RED Refrigeration and/or Evacuation Hose (SAEJ2196/R-134a)2. Hose Fitting (0.5-16 Acme)3. YELLOW Refrigeration and/or Evacuation Hose(SAE J2196/R-134a)4. Hose Fitting with O-ring (M14 x 1.5)5. High Side Field Service Coupling (Red Knob)6. BLUE Refrigeration and/or Evacuation Hose (SAEJ2196/R-134a)7. Low Side Field Service Coupling (Blue Knob)- - - - -7.3 SERVICE VALVESCompressor suction, compressor discharge, and liquidline service valves (see Figure 7.3) are provided with adouble seat and a gauge connection, which enablesservicing of the compressor and refrigerant lines.Turning the valve stem clockwise (all the way forward)will frontseat the valve to close off the suction, dis-charge or liquid line and open the gauge port to thecompressor or low side. Turning the stem counter-clockwise (all the way out) will backseat the valve toopen the connections and close off the port.With the valve stem midway between frontseat andbackseat, both of the service valve connections areopen to the access valve path.For example, the valve stem is first fully backseatedwhen connecting a manifold gauge to measure pres-sure. Then, the valve is opened 1/4 to 1/2−turn to mea-sure the pressure.Figure 7.3 Service Valve1. Line Connection2. Access Valve3. Stem Cap4. Valve stem5. Compressor or Filter Drier Inlet Connection6. Valve (Frontseated)7. Valve (Backseated)- - - - -Connection of the manifold gauge/hose set (see Fig-ure 7.4) is dependent on the component being ser-viced. If only the compressor is being serviced, thehigh side coupling is connected to the discharge ser-vice valve.For service of the low side (after pump down), the highside coupling is connected to the liquid line servicevalve. The center hose connection is brought to thetool being used (vacuum, tank, etc.).Connecting the manifold gauge set:a. Remove service valve stem cap and make surethe valve is backseated.b. Remove service port cap (See Figure 7.3).c. Connect the high side field service coupling (seeFigure 7.2) to the discharge or liquid line valveservice valve port.d. Turn the high side field service coupling knob(red) clockwise, which will open the high side ofthe system to the gauge set.e. Connect the low side field service coupling tothe suction service valve port.f. Turn the low side field service coupling knob(blue) clockwise, which will open the low side ofthe system to the gauge set.g. To read system pressures, slightly midseat thehigh side and suction service valves.CAUTION!To prevent trapping liquid refrigerant inthe manifold gauge set, be sure set isbrought to suction pressure before dis-connecting.To Low SideAccess ValveTo High SideAccess Valve123245647123456 7Downloaded from ManualsNet.com search engine