Carrier 50PG20-28 Controls, Start-up, Operation, Service And Troubleshooting Instructions

Also see for 48PG20---28: User's information manual User's information manual Installation and service instructions

Carrier 50PG20-28 Controls, Start-up, Operation, Service And Troubleshooting Instructions Manual pdf 89 page image

5OOO45OO4OOO35OO3000o 25002000150010005OOLEAK INVACUUM TIGHTTOO WETTIGHTDRY SYSTEM0 1 2 3 4 5 6 7MINUTESFig. 41 -- Deep Vacuum GraphTRIPLE EVACUATION METHOD The triple evacumionmethod should only be used when vacuum pump is capable ofpumping down to 28 in. of mercury and system does not con-tain any liquid ,a_ater.Proceed as follows:1. Pump system down to 28 in. of mercury and allow pumpto continue operating for an additional 15 minutes.2. Close service valves and shut off vacuum pump.3. Connect a nitrogen cylinder and regulator to system andopen until system pressure is 2 psig.4. Close service valve and allow system to stand for 1 hr.During this time, dry nitrogen will be able to diffusethroughout the system, absorbing moisture.5. Repeat this procedure. System will then contain minimalamounts of contmninants and water vapor.Refrigerant Charge -- Amount of refrigerant charge islisted on unit nameplate. Refer to Carrier GTAC II; Module 5;ChaNing, Recovery, Recycling, and Reclmnation section forcharNng methods and procedures. Unit panels must be in placewhen unit is operating during charging procedure.Puron_r9(R-410A) refrigerant cylinders contain a dip tubewhich allows liquid refiigerant to flow tiom the cylinder in anupright position. ChaNe units with cylinder in the uprightposition and a colrnnercial type metering device in the mani-fold hose.TO USE THE COOLING CHARGING CHART, STAN-DARD UNITS Use the above temperature and pressurereadings, and find the intersection point on the cooling chaN-ing chart. If intersection point on chart is above line, add refiig-erant. If intersection point on chart is below line, carefully re-cover some of the charge. Recheck suction pressure as chargeis adjusted.CHARGING CHART (ALL CIRCUITS)ALL OUTDOORFANS MUST BE OPERATING150 ?00 _50 SO0 aS0 Io0 IS0 500 550Liquid Pressure el Liqu{d V0{_e, [psig]qqHHHH'1!Fig. 42 -- Charging Chart -- 48/50PG20 --Standard UnitCHARGING CHARTALL OUTDOOR FANS MUST BE OPERATINGLiquid Pressure at Liquid Valve, [psig]This system uses Puron refi'igerant which Ms higherpressures than R-22 and other refiigerants. No other refrig-erant may be used in this system. Gage set, hoses, andrecovery system must be desigqed to handle Puron refrig-erant. If unsure about equipment, consult the equipmentmanuthcturer.NOTE: Do not use recycled refiigerant as it may containcontaminants.NO CHARGE Use standard evacuating techniques. Afterevacuating system, weigh in the specified amount of refiiger-ant (refer to unit nameplate).NOTE: System chmge for units with Humidi-MiZer TM systemis greater than the system charge of the standard unit.LOW CHARGE COOLING Using cooling chmging chart(see Fig. 42-45), add or relnove refiigerant until conditions of thechart are met. An accurate pressure gage and telnperature-sensing device are required. Charging is accomplished byensuring the proper amount of liquid subcooling. Measure liquidline pressure at the liquid line service valve using pressure gage.Connect telnperature sensing device to the liquid line near theliquid line service valve and insulate it so that outdoor ambienttemperature does not affect reading.Fig. 43 -- Charging Chart -- 48/50PG20 --Unit with Humidi-MiZeW MSystemCHARGING CHART (ALL CIRCUITS)ALL OUTDOOR FANS MUST BE OPERATING_so 2oo 25o sou &5o _oo aso 500 sso 6ooLiquid Pressure o_ Liquid Volve, [psig}Fig. 44 -- Charging Chart -- 48/50PG24 -- StandardUnit and Unit with Humidi-MiZeW MSystem89