R-410A safety & Training Exam Questions and Answers 2024

Recovery cylinders used with R-410A must have a DOT rating of: - either "DOT 4BA 400" or "DOT 4BW 400" A system using R-410A refrigerant has bubbles in the sight glass. Technician A says that the system must be low on refrigerant. Technician B says that the bubbles could be caused by the blended refrigerant flashing in the increased volume of the sight glass. Who is correct? - Technician B only When charging a R-410A system that uses a thermostatic expansion valve, proper charge can be determined by measuring - Subcooling When charging a R-410A system that uses a capillary tube or fix metering device, proper charge can be determined by measuring - Superheat Compressor internal pressure relief (IPR) settings for R-410A systems are: - 550 psig to 625 psig When handling refrigerants, technicians should: - Where approved eye protection and gloves R-410A systems use a high pressure switch that will open at approximately: - 610 psig plus or minus 10 psig Subcooled liquid in the receiver may ______________ subcooling, depending on surrounding conditions. - either "lose" or "gain" When installing a liquid line filter dryer on a R-410A system, be certain that it has a pressure rating of at least: - 600 pisg The flow area of a R-410A metering device is: - Smaller than that of a R-22 metering device Which of the following statements is true of R-407C - It may separate (fractionate) into its component refrigerants A true Azeotropic blend - Has no temperature glide, will not fractionate, and behaves as a single component refrigerant When a blend is zeotropic, or near-azeotropic (NARM), - It will have temperature glide, it can fractionate, and leaks may cause a change in composition of the bland R-410A is also known as - Suva 410A, AZ-20, and Puron The temperature glide for R-410A is less than _____________ degrees Fahrenheit over air conditioning and refrigerating operating ranges. - 0.3 Polyol Ester (POE) - Is hygroscopic, can be irritating to the skin, and has improved heat transfer characteristics over mineral oils The low pressure control on R-410A system will open at: - 50 pisg Compression ratio is calculated as: - Absolute discharge pressure divided by absolute suction pressure Both suction and discharge pressure of R-410A system are_______________ then R-22 system. - 40% to 70% higher Because of its higher vapor heat capacity, the discharge temperature of R-410A is ____________ then R-22. - lower When a blend is zeotropic, or near-azeotropic (NARM), - It should be transferred from cylinders as a liquid to avoid fractionation Near-azeotrope blend fractionation may; - Cause the components to leak at uneven rates due to varying vapor pressures Blends that have fractionated, depending on the constituent make-up, may become; - Flammable To avoid fractionation, blended refrigerants: - Should be charged in the liquid phase When charging an operating R-410A system with liquid refrigerant, - Be sure it is throttled into the low side to avoid compressor damage The closer a blend comes to being a true azeotrope, - The less temperature glide it will have Cylinders containing R-410A that are equipped with dip tubes, - To allow liquid to be removed with the cylinder upright Temperature glide refers to - A range of condensing and evaporating temperatures for one pressure When calculating subcooling with R-407C - Use the bubble point value only When calculating superheat with R-407C - Use the dew point value only