8. Nate Industry Competency Exam: Commercial Refrigeration

What would result in an evaporator having low pressure and low superheat? a. Lack of airflow across the evaporator b. Restricted liquid line filter-drier c. Lack of refrigerant in the evaporator d. Refrigerant overcharge {Ans: A}Using the illustration below, what is the pressure drop across the refrigerant distributor and distributor tubes? a. 2.5 psi. b. 35 psi. c. 71 psi. d. 120 psi. {Ans: B}In an oil separator, a collapsed float will cause: a. The valve to stay closed. b. Head pressure to rise. c. The valve to stay open. d. Liquid refrigerant to short-circuit to the crankcase. {Ans: A}Which of the following should be used to determine that the thermistor on refrigeration equipment is functional? a. Ohmmeter. b. Millivoltmeter. c. Milliammeter. d. Microammeter. {Ans: A}On a new installation, the purpose of adjusting a thermostatic expansion valve to maintain a low superheat is to ensure that: a. The liquid refrigerant will boil off as quickly as possible in the evaporator. b. The majority of the evaporator surface is active. c. Liquid refrigerant will flow back to the compressor. d. Suction pressure at the evaporator will remain constant. {Ans: B}When charging a R-400 series refrigerant into