Carrier 38C Series Installation, Operation And Maintenance Manual

Contents

ServiceOutdoor Fan— A reinforced wire mount holds the outdoor fan assembly in place.Compressor Pressure Relief Valve — Valve is located in compressor. Relief valve opens at a pressure differential ofapproximately 600 ± 50 psig between suction (low side) and discharge (high side) to allow pressure equalization.Internal Current and Temperature Sensitive Overload — Control resets automatically when internal compressormotor temperature drops to a safe level (overloads may require up to 45 minutes to reset). When an internaloverload is suspected of being open, check by using an ohmmeter or continuity tester. If necessary, refer to CarrierStandard Systems Techniques Manual, Chapter 2, for complete information.Pump down Procedure — Service valves provide a convenient shut-off valve useful for certain refrigeration systemrepairs. System may be pumped down to make repairs on low side without losing complete refrigerant charge.1. Attach pressure gage to suction service valve gage port.2. Front seat the liquid line valve.3. Start unit in cooling mode. Run until low-pressure switch opens at 54 psig (472Kpa). Do not allow compressorto pump to a vacuum.4. Shut unit off and front seat suction valve.5. Depressurize low side of unit and recover refrigerant following accepted practice.Filter Drier – The filter drier is specifically designed to operate with R-410A, use only factory-authorized components.When removing a filter drier, use a tubing cutter to cut drier from system. Do not unsweat a filter drier from system.Heat from unsweating will release moisture and contaminants from drier into the system.Loss of Charge Pressure Switch — This switch, mounted on the suction line, has fixed non-adjustable settings. Tocheck pressure switch, attach pressure gage to suction service valve gage port. Slowly close liquid shutoff valve andallow compressor to pump down. Do not allow compressor to pump down below 2 psig. Compressor should shutdown when suction pressure drops to cutout pressure in Physical Data Table, and should restart when pressurebuilds up to cut-in pressure shown in Physical Data Table.High Pressure Switch — This switch, mounted on the discharge line, has fixed non- adjustable settings & autoreset. To check pressure switch, attach pressure gauge to compressor discharge service port, block condenser coil,monitor pressure till compressor trips, remove blockage and observe at which pressure compressor restarts.The 38C unit coils hold only the factory designated amount of refrigerant. Additional refrigerant may causeunits to relieve pressure through compressor internal pressure relief valve (indicated by sudden rise of suctionpressure) before suction pressure reaches 5 pisg. If this occurs, shut off immediately, then front seat thesuction valve and remove and recover excess refrigerant following accepted practice.CautionBefore performing service or maintenance, be sure the indoor unit main power switch is off and indoor blowerhas completely stopped. Failure to do so may result in electrical shock or injury from rotating fan blades.WarningDo not leave system open to atmosphere. Product damage could occur. Compressor oil is highly susceptible tomoisture absorption.CautionThe compressor used in this product is specifically designed to operate with R-410A refrigerant and cannot beinterchanged.CautionPage 13