Carrier 38AUM Series Installation, Operation & Maintenance Manual

Contents

Carrier 38AUM Series Installation, Operation & Maintenance Manual Manual pdf 38 page image

ATTENTION INSTALLERS AND SERVICE TECHNICIANS!R-410A Refrigerant Quick Reference Guide• R-410A refrigerant operates at 50-70 percent higher pressures than R-22. Be sure that servicing equipmentand replacement components are designed to operate with R-410A refrigerant.• R-410A refrigerant cylinders are rose colored.• Recovery cylinder service pressure rating must be 400 psig, DOT 4BA400 or DOT BW400.• R-410A refrigerant systems should be charged with liquid refrigerant. Use a commercial type meteringdevice in the manifold hose when charging into suction line with compressor operating.• Manifold sets should be 700 psig high side and 180 psig low side with 550 psig low-side retard.• Use hoses with 700 psig service pressure rating.• Leak detectors should be designed to detect HFC refrigerant.• R-410A refrigerant, as with other HFCs, is only compatible with POE oils.• Vacuum pumps will not remove moisture from oil.• Do not use liquid-line filter driers with rated working pressures less than 600 psig.• Do not leave R-410A refrigerant suction line filter driers in line longer than 72 hours.• Do not install a suction-line filter drier in liquid-line.• POE oils absorb moisture rapidly. Do not expose oil to atmosphere.• POE oils may cause damage to certain plastics and roofing materials.• Wrap all filter driers and service valves with wet cloth when brazing.• A factory-approved liquid-line filter drier is required on every unit.• Do NOT use an R-22 expansion device.• If indoor unit is equipped with an R-22 expansion device, it must be changed to a hard-shutoff R-410Arefrigerant expansion device.• Never open system to atmosphere while it is under a vacuum.• When system must be opened for service, recover refrigerant, evacuate then break vacuum with drynitrogen and replace filter driers. Evacuate to 500 microns prior to recharging.• All indoor coils must be installed with a hard-shutoff R-410A refrigerant expansion metering device.• Do not vent R-410A refrigerant into the atmosphere.• Do not use capillary tube coils.• Observe all warnings, cautions, and bold text.Page 38