Carrier 50TC*17 Series Service And Maintenance Instructions

19PURON (R−410A) REFRIGERANTThis unit is designed for use with Puron (R−410A)refrigerant. Do not use any other refrigerant in thissystem.UNIT DAMAGE HAZARDFailure to follow this CAUTION can result in damage tocomponents.The compressor is in a Puron (R−410A) refrigerantsystem and uses a polyester (POE) oil. This oil isextremely hygroscopic, meaning it absorbs waterreadily. POE oils can absorb 15 times as much water asother oils designed for HCFC and CFC refrigerants.Avoid exposure of POE oil to the atmosphere. Exposureto the atmosphere can cause contaminants that areharmful to R−410A components to form. Keep POE oilcontainers closed until ready for use.CAUTIONPuron (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, with theaccess valve located on the bottom,when adding liquid 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 when breaking therefrigerant system vacuum while the compresor is OFF.Only add refrigerant (liquid) into the suction line whilethe compressor is operating. If adding refrigerant into thesuction line, use a commercial metering/expansion deviceat the gauge manifold; remove liquid from the cylinder,pass it through the metering device at the gauge set, andthen pass it into the suction line as a vapor. Do not removePuron (R−410A) refrigerant from the cylinder as avapor.Refrigerant ChargeUnit panels must be in place when the unit is operatingduring the charging procedure. To prepare the unit forcharge adjustment:No ChargeUse standard evacuating techniques. Evacuate the systemdown to 500 microns and let set for 10 minutes todetermine if the system has a refrigerant leak. If theevacuation level raises to 1100 microns and stabilizes,then the system has moisture in it and should bedehydrated as GTAC2-5 recommends.If the system continues to rise above 1100 microns, thenthe system has a leak and should be pressurized and leaktested using appropriate techniques as explained inGTAC2-5. After evacuating the system, weigh in thespecified amount of refrigerant as listed on the unit'srating plate.Low−Charge CoolingUsing the Cooling Charging Charts (Figs. 23 thru 30),vary the refrigerant until the conditions of the appropriatechart are met. Note the charging charts are different fromthe type normally used. These charts are based oncharging the units to the correct superheat for the variousoperating conditions. Accurate pressure gauge andtemperature sensing devices are required. Connect thepressure gauge to the service port on the suction line.Mount the temperature sensing device on the suction lineand insulate it so the outdoor ambient temperature doesnot affect the reading. Indoor-air cfm must be within thenormal operating range of the unit.SIZE DESIGNATION NOMINAL TON REFERENCE17 1520 17.524 2028 25EXAMPLE:Model 50TC*D28Circuit AOutdoor Temperature 85F (29C). . . . . . . . . . . . . . . . . .Suction Pressure 125 psig (860 kPa). . . . . . . . . . . . . . . . .Suction Temperature should be 63F (17C). . . . . . . . . .Circuit BOutdoor Temperature 85F (29C). . . . . . . . . . . . . . . . . .Suction Pressure 120 psig (830 kPa). . . . . . . . . . . . . . . . .Suction Temperature should be 58F (14C). . . . . . . . . .Using the Cooling Charging ChartsTake the outdoor ambient temperature and read thesuction pressure gauge. Refer to the chart to determinewhat the suction temperature should be. If the suctiontemperature is high, add refrigerant.If the suction temperature is low, carefully recover someof the charge. Recheck the suction pressure as the chargeis adjusted.Select the appropriate unit charging chart from Figs. 22thru 29.Note the outdoor ambient temperature and read thesuction pressure gauge. Refer to the chart to determinewhat the suction temperature should be. If the suctiontemperature is high, add refrigerant. If the suctiontemperature is low, carefully recover some of the charge.Recheck the suction pressure as the charge is adjusted.For 17–28 sizes, perform this procedure once for CircuitA (using the Circuit A chart) and once for Circuit B (usingthe Circuit B chart).