R-410A Final Exam With Questions And Answers

R-410A FINAL EXAM WITH QUESTIONS AND ANSWERS Because of its higher vapor heat capacity, the discharge temperature of R-410A is ________ than R22 - ANSWER Lowe Both suction and discharge pressures of R-410A systems are _____ than R- 22 systems - ANSWER 40% to 70% higher The temperature glide for R-410A is less than ______ degrees Fahrenheit over air conditioning and refrigerating operating ranges - ANSWER 0.3 Compression ratio is calculated as: - ANSWER Absolute discharge p ressure divided by absolute suction pressure Polyol Ester (POE) - ANSWER Can be irritating to the skin, is hygroscopic, has improved heat transfer characteristics over mineral oils The low pressure control on R-410A systems will open at: - ANSWER 50 psig When a blend is zeotropic, or near-azeotropic (NARM): - ANSWER * Leaks may cause a change in the composition of the blend * It will have a temperature glide * It can fractionate R-410A systems use a high-pressure switch that will open at approximately? - ANSWER 610 psig plus or minus 10 psig A true azeotropic blend: - ANSWER * Will not fractionate * Has no temperature glide * Behaves as a single component refrigerant Subcooled liquid in the receiver may _____ subcooling, depending on surrounding conditions. - ANSWER Lose/gain Which of following statements is true of R-407C - ANSWER It may separate (fractionate) into its components refrigerants R-410A is also known as? - ANSWER * Suva 410A * AZ- 20 * Puron When installing a liquid line filter drier on an R-410A system, be certain that it ha s a pressure rating of at least: - ANSWER 600 psig The flow area of a R410a metering device is: - ANSWER Smaller than that of a r22 metering device Temperature glide refers to: - ANSWER A range of condensing and evaporating temperatures for one pressure When a blend is zeotropic, or near-azeotropic (NARM): - ANSWER It should be transferred from cylinders as a liquid to avoid fractionation Cylinders containing R410a that are equipped with dip tubes: - ANSW ER To allow liquid to be removed with the cylinder upright Near-azeotropic blend fractionation may: - ANSWER Cause the components to leak at uneven rates due to varying vapor pressures The closer a blend comes to being a true azeotrope: - ANSWER The less temperature glide it will have Blends that have fractionated, depending on the constituent make-up , may become: - ANSWER flammable When charging an operating R-410A system with liquid refrigerant: - ANSW ER Be sure it is throttled into the low side to avoid compressor damage To avoid fractionation, blended refrigerants: - ANSWER Should be charged in t he liquid phase