Carrier 69NT40-541-505 Operation And Service Manual

7–5 T-3687.7.1 Checking the Refrigerant ChargeNOTETo avoid damage to the earth’s ozone layer,use a refrigerant recovery system wheneverremoving refrigerant. When working withrefrigerants you must comply with all localgovernment environmental laws. In the U.S.,refer to EPA section 608.a. Connect the gauge manifold to the compressordischarge and suction service valves.b. Bring the container temperature to approxi-mately 1.7°C (35°F) or -17.8°C (0°F). Set thecontroller set point to -25°C (-13°F) to ensurethat the suction modulation valve is at maximumallowed open position.c. Partially block the condenser coil inlet air. If cov-ering the lower portion of the coil is not sufficient,remove the left hand infill panel and cover the leftside of the coil. Increase the area blocked untilthe compressor discharge pressure is raised toapproximately 12.8 bar (185 psig).d. On the receiver, the level should be between theglasses. If the refrigerant level is not correct,continue with the following paragraphs to add orremove refrigerant as required.7.7.2 Adding Refrigerant to System (FullCharge)a. Evacuate unit and leave in deep vacuum (referto Section 7.6).b. Place cylinder of R-134a on scale and connectcharging line from cylinder to liquid line valve.Purge charging line at liquid line valve and thennote weight of cylinder and refrigerant.c. Open liquid valve on cylinder. Open liquid linevalve half-way and allow the liquid refrigerant toflow into the unit until the correct weight of refrig-erant (refer to Section 3.2) has been added asindicated by scales.NOTEIt may be necessary to finish charging unitthrough suction service valve in gas form,due to pressure rise in high side of the sys-tem (refer to Section 7.7.3).d. Backseat manual liquid line valve (to close offgauge port). Close liquid valve on cylinder.e. Start unit in cooling mode. Run approximately10 minutes and check the refrigerant charge.7.7.3 Adding Refrigerant to System (PartialCharge)a. Examine the unit refrigerant system for any evi-dence of leaks. Repair as necessary (refer toSection 7.5).b. Maintain the conditions outlined in Section 7.7.1.c. Fully backseat the suction service valve andremove the service port cap.d. Connect charging line between suction servicevalve port and cylinder of refrigerant R-134a.Open VAPOR valve.e. Partially frontseat (turn clockwise) the suctionservice valve and slowly add charge until therefrigerant appears at the proper level.7.8 COMPRESSORWARNING!Make sure power to the unit is OFF andpower plug disconnected before replac-ing the compressor.NOTES1. The compressor should not operate in a vacuumgreater than 500mm/hg (20 inches/hg).2. The service replacement compressor is soldwithout shutoff valves (but with valve pads), andwithout terminal box and cover. Customershould retain the original terminal box, cover,and high pressure switch for use on replace-ment compressor.3. Check oil level in service replacement compres-sor (refer to Section 7.8.6).4. A compressor terminal wiring kit must beordered as a separate item when orderingreplacement compressor. Appropriate installa-tion instructions are included with kit.5. Refer to Table 7–4 and Table 7–5 for applicablecompressor wear limits and torque values.6. Refer to Figure 7.31 for charts on compressorpressure, temperature and motor currentcurves.7.8.1 Removal and Replacement of Compressora. Remove the protective guard from lower sectionof the unit.b. Pump down low side (refer to Section 7.4) orfrontseat compressor service valves andremove refrigerant from compressor using arefrigerant recovery system.c. Locate the compressor junction box. Tag anddisconnect wiring from compressor terminalsand remove compressor junction box.d. Loosen service valve mounting bolts, breakseal, and then remove bolts.e. Remove compressor plate mounting bolts.f. Remove compressor and mounting plate. Referto Section 3.2 for weight of compressor.Downloaded from ManualsNet.com search engine