Carrier 38AU Installation, Start-up And Service Instructions Manual

Also see for 38AU: Installation, Start-Up and Service Instructions Installation, Start-Up and Service Instructions

Carrier 38AU Installation, Start-up And Service Instructions Manual Manual pdf 17 page image

17The stub tube connections include 1 / 4 -in SAE servicefittings with Schrader valve cores (see Fig. 10). Beforemaking any brazed connections to the unit service valves,remove both Schrader valve caps and cores and save forre-installation. Connect a source for nitrogen to one ofthese service fittings during tube brazing to prevent theformation of copper oxides inside the tubes at brazedjoints.FactoryHigh-FlowAccess PortService Valvewith Stem CapField ServiceAccess Port(Schrader core)SweatConnectionC10203Fig. 10 -- Typical Piping Connection AssemblyWhen connecting the field tubing to the 38AU servicevalves, wrap the valves in wet rags to prevent overheatingPressure-test all joints from outdoor unit connections overto the evaporator coil, using nitrogen as pressure and withsoap-and-bubbles.When pressure-testing is completed, remove the nitrogensource at the outdoor unit service valves and re-install thetwo Schrader valve cores. Torque the cores to 2-3 in-lbs(23-34 N-cm).Evacuation/Dehydration —Evacuate and dehydrate the connected refrigerationsystem(s) (excluding the 38AU unit) to 500 microns usinga two-stage vacuum pump attached to the service portsoutside the 38AU service valves, following description inGTAC II, Module 4, System Dehydration.UNIT OPERATION AND SAFETY HAZARDFailure to follow this warning could cause personalinjury, death and/or equipment damage.PuronR (R--410A) refrigerant systems operate athigher pressure than standard R--22 systems. Do notuse R--22 service equipment or components on Puronrefrigerant equipment.! WARNINGThis unit is designed for use with Puron (R--410A)refrigerant. Do not use any other refrigerant in thissystem.Puron (R--410A) refrigerant is provided in pink (rose)colored cylinders. These cylinders are available with andwithout dip tubes; cylinders with dip tubes will have alabel indicating this feature. For a cylinder with a diptube, place the cylinder in the upright position (accessvalve at the top) when removing liquid refrigerant forcharging. For a cylinder without a dip tube, invert thecylinder (access valve on the bottom) when removingliquid refrigerant.Because Puron (R--410A) refrigerant is a blend, it isstrongly recommended that refrigerant always be removedfrom the cylinder as a liquid. Admit liquid refrigerant intothe system in the discharge line. If adding refrigerant intothe suction line, use a commercial metering/expansiondevice at the gauge manifold; remove liquid from thecylinder, pass it through the metering device at the gaugeset and then pass it into the suction line as a vapor. Do notremove Puron (R–410A) refrigerant from the cylinder as avapor.Preliminary Charge —Before starting the unit, charge R-410A liquid refrigerantinto the high side of each 38AU circuit through the liquidservice valve(s). The amount of refrigerant added must beat least 80% of the operating charge listed in Tables 5 or 6for LINEAR line length LESS the factory charge quantity(if factory shipping charge has not been removed). Seeexample below.Allow high and low side pressures to equalize. If pressuresdo not equalize readily, charge R-410A vapor (using spe-cial service manifold with expansion device) into the suc-tion line service port for the low side of system to assurecharge in the evaporator. Refer to GTAC II, Module 5,Charging, Recover, Recycling, and Reclamation for liquidcharging procedures.Example:38AUD*25 (RTPF)60-ft (18.3 m) linear line lengthEquivalent line length 90-ft (27.4 m)Liquid Lift: 20-ft (6.1 m)Select line sizes from Table 6 (38AUD):Liquid 1 / 2 inSuction 1- 1 / 8 in.ChargeCircuit 1: 23.0 lbs (at 75-ft linear length)Circuit 2: 22.0 lbs80% of Operating Charge:Circuit 1: 0.80 x 23.0 = 18.4 lbsCircuit 2: 0.80 x 22.0 = 17.6 lbsFactory Shipping Charge: 15 lbsField-ChargeCircuit 1: 18.4 -- 15 = 3.4 lbsCircuit 2: 17.6 -- 15 = 2.6 lbsFor linear line lengths longer than 125 ft (38 m), contactyour local Carrier representative for system charge value.Step 6 — Install AccessoriesAccessories requiring modifications to unit wiring shouldbe completed now. These accessories may include WinterStart controls and Low Ambient controls. Refer to theinstructions shipped with the accessory.38AU