Carrier 38AUZ*07 Series Installation, Start-up And Service Instructions Manual

Contents

13Table 9 — Refrigerant Specialities Part Numbers.Refer to Table 9 for recommendations on refrigerationspecialties.In some applications, depending on space and convenience re-quirements, it may be desirable to install 2 filter driers and sightglasses in a single circuit application. One filter drier and sightglass may be installed at A locations in Fig. 7, or 2 filter driersand sight glasses may be installed at B locations.Select the filter drier for maximum unit capacity and minimumpressure drop. Complete the refrigerant piping from the indoorunit to the outdoor unit before opening the liquid and suctionlines at the outdoor unit.INSTALL LIQUID LINE SOLENOID VALVE —It is recommended that a solenoid valve be placed in the mainliquid line (see Fig. 7) between the condensing unit and theevaporator coil. Locate the solenoid valve at the outlet end ofthe liquid line, near the evaporator coil connections, with flowdirection arrow pointed at the evaporator coil. Refer to Table 9.(A liquid line solenoid valve is required when the liquid linelength exceeds 23 m [75 ft].) This valve prevents refrigerantmigration (which causes oil dilution) to the compressor duringthe off cycle, at low outdoor ambient temperatures. Wire thesolenoid in parallel with the compressor contactor coil (seeFig. 7). This means of electrical control is referred to as sole-noid drop control.CAPACITY CONTROL LIQUID LINE SOLENOID VALVEEvaporator capacity control via liquid solenoid valve is not rec-ommended for use with 38AU models.MAKE PIPING CONNECTIONS — Piping connections atthe 38AU unit are ball valves with stub tube extensions. Do notopen the unit service valves until all interconnecting tube braz-ing as been completed.The stub tube connections include ¼-in SAE service fittingswith Schrader valve cores (see Fig. 9). Before making anybrazed connections to the unit service valves, remove bothSchrader valve caps and cores and save for re-installation. Con-nect a source for nitrogen to one of these service fittings duringtube brazing to prevent the formation of copper oxides insidethe tubes at brazed joints.When connecting the field tubing to the 38AU service valves,wrap the valves in wet rags to prevent overheatingPressure-test all joints from outdoor unit connections over tothe evaporator coil, using nitrogen as pressure and with soap-and-bubbles.When pressure-testing is completed, remove the nitrogensource at the outdoor unit service valves and re-install the twoSchrader valve cores. Torque the cores to 23-34 N-cm(2-3 in-lbs).Fig. 7 — Location of Sight Glass(es) and Filter DriersTypical 38AUZ SystemsLIQUID LINESIZE (in.)LIQUID LINESOLENOID VALVE (LLSV)LLSVCOILSIGHTGLASSFILTERDRIER3 / 8 ALC-066208 AMG-24/50-60 HMI-1TT3 Provided with unitSee Table 81 / 2 ALC-066209 AMG-24/50-60 HMI-1TT45 / 8 ALC-066212 AMG-24/50-60 HMI-1TT538AUD units require TWO sets of parts.INDOORCOIL CKT 2AIRFLOWINDOORCOIL CKT 1AIRFLOW15 DIAMSMIN 10DIAMS8 DIAMSMINTXVSENSINGBULBEQUALIZER LINESIGHT GLASSA LOCATIONSIGHTGLASSESB LOCATIONTXVCKT 2FILTER DRIERA LOCATIONFILTERDRIERSB LOCATIONDROPCONTROLSOLENOIDVALVEFLOWTXVSENSINGBULBTXVCKT 18 DIAMSMIN15 DIAMSMIN 10DIAMSSingle Circuit Coil Piping ConfigurationFor single compressor condensing unitsDual Circuit Coil Piping ConfigurationFor single compressor condensing units15 DIAMSMIN 10DIAMS8 DIAMSMININDOORCOIL CKTAIRFLOWTXVSENSINGBULBEQUALIZER LINESIGHT GLASSA LOCATIONTXV FILTER DRIERA LOCATIONDROPCONTROLSOLENOIDVALVEFLOWLEGENDTXV — Thermostatic Expansion Valve