Carrier Gemini 38AU07 Series Installation Instructions Manual

Contents

1138AUD PIPING CONNECTIONSThe 38AUD unit’s two circuits are designated Circuit 1and Circuit 2. Circuit 1 is controlled by the thermostat’s Y1(or TC1) contact and will be the first circuit on and last circuitoff. Circuit 2 is controlled by the thermostat’s Y2 (or TC2)contact and this circuit is always the “lag” circuit.See Fig. 7 for location of Circuit 1 and Circuit 2 servicevalves and field piping connections. Circuit 1 is on the right-hand side of the service valve compartment; Circuit 2 is onthe left.When a single piece evaporator coil with two separate cir-cuits is connected to a 38AUD, the lower coil circuit shouldbe connected to the 38AUD unit’s Circuit 1 so that the evapo-rator’s lower coil segment is first-on/last-off (to avoid re-evaporation of condensate on dry lower coil segments).Fig. 7 — 38AUD Service Valve LocationsPlan the Circuit 1 and Circuit 2 tubing segments carefully,mark each segment and check constantly as piping systemsare assembled to avoid piping errors.38AUD unit cannot be field-piped as a single-circuit/tandemsystem.FINAL TUBING CHECK. 38AUDBefore completing the field piping connections to the38AUD unit service valves, confirm that the suction line to theindoor coil’s first-on/last-off circuit (and its companion liquidline) are correctly identified as Circuit 1 use for the 38AUDunit. If a suction riser is required, it must be in Circuit 1.Connecting 40RU to 38AUDThe 40RU fan coil in sizes 12, 14 and 16 is a face-split coildesign that also has its circuits designated as 1 and 2. SeeFig. 8. Note that the lower coil segment changes as the ar-rangement of the 40RU changes. In a vertical arrangement,the 40RU unit’s lower coil segment is segment 2; this seg-ment should be connected to the 38AUD unit’s Circuit 1. In ahorizontal arrangement, the 40RU unit’s lower segment isnow segment 1; this segment should be connected to the38AUD unit’s Circuit 1.Note that refrigerant suction piping should be insulated.Fig. 8 — Typical Evaporator Coil Connections(40RU)INSTALL FILTER DRIER(S) AND MOISTURE INDICA-TOR(S)Every unit MUST have a filter drier in the liquid line.38AUD models require two filter driers (one in each liquidline). Locate the filter drier(s) at the indoor unit, close to theevaporator coil’s thermal expansion valve (TXV) inlets.The 38AU units include one (38AUZ) or two (38AUD)Puron-duty filter drier(s), shipped in cartons attached to theunit basepan (see Table 11). Remove the filter drier(s) andprepare to install in the liquid line(s) at the evaporator coil.Do not remove connection fitting plugs until ready to connectand braze the filter drier into the liquid line position.Table 11 — Puron-duty Filter Drier(s)Installation of liquid line moisture indicating sightglass ineach circuit is recommended. Locate the sightglass(es) betweenthe outlet of the filter drier and the TXV inlet.Refer to Table 12 for recommendations on refrigerationspecialties.In some applications, depending on space and conve-nience requirements, it may be desirable to install 2 filter dri-ers and sight glasses in a single circuit application. One filterdrier and sight glass may be installed at A locations (see Fig.9) or 2 filter driers and sight glasses may be installed at B lo-cations (see Fig. 9 and 10).40RUARRANGEMENTCOOLINGSTAGE40RU COILSEGMENTCONNECT TO38AUDVertical Y1 2 Circuit 1Y2 1 Circuit 2Horizontal Y1 1 Circuit 1Y2 2 Circuit 2Circuit 1ConnectionsCircuit 2ConnectionsCKT2 CKT1MODELSIZE QTY LIQUID LINEOD (in.) DESICCANTVOLUMEPARTNUMBERREF.38AUZ*07 1 3 / 8 8 cu in. KH43LG09138AUZ*07 1 1 / 2 16 cu in. KH43LG08538AUZ*07 1 1 / 2 16 cu in. KH43LG08538AUZ*07 1 5 / 8 16 cu in. KH43LG08638AUD*12 2 3 / 8 8 cu in. KH43LG09138AUD*14 2 1 / 2 16 cu in. KH43LG085CONDENSATE DRAIN CONNECTIONCONDENSATE DRAINCONNECTIONSUCTION-VAPORCONNECTIONLIQUID LINECONNECTIONFIRST ON/LAST OFF = 2VERTICAL INSTALLATIONFIRST ON/LAST OFF = 1HORIZONTAL INSTALLATION