NATE Light Commercial Refrigeration Exam Questions and Correct Answers, Exams of Nursing

Download NATE Light Commercial Refrigeration Exam Questions and Correct Answers and more Exams Nursing in PDF only on Docsity! NATE Light Commercial Refrigeration  What is the MOST important aspect about installing a rooftop package unit? - Answer The roof will support the weight What could be at fault of an air cooled system that operates 50°F over ambient temperature? - Answer An overcharge, air in the system, or air re-circulating over the condenser Where should the sensing bulb on a TXV be located? - Answer As close to the evaporator as possible on a horizontal line When a transformers secondary windings are wired in parallel, it is important to wire them ____________ - Answer In phase with each other If a single phase compressor is cycling on its overload protector, what should be checked? - Answer Voltage input, test capacitors, start relays, and motor windings. What is the maximum pressure drop across an R-404A suction line filter dryer? - Answer 2 PSI (2 degree saturation temp) What type of maintenance do water cooled condensers require? - Answer Clean the coil with scale remover and adjust the water valve If a CSR motor starts and operates with a high amperage, what could be at fault? - Answer A faulty run capacitor What causes excessive head pressure on water cooled condensers? - Answer Fouled condenser water, dirty water cooled condenser, over charge and air trapped in the condenser What happens during a hot pull down? - Answer The refrigeration system works hard and for low temperature systems a CPR (crankcase pressure regulator) is used to prevent compressor overloading What will ice on the ceiling and floor of a walk-in freezer typically indicate? - Answer A plugged drain line or a defective drain pan heater Name some ways to maintain head pressure during low ambient conditions - Answer Reduce the airflow over the condenser by a reverse acting high pressure switch, an electronic fan speed control, or louvers or use a head pressure control regulating valve (HPR) to back flood the condenser What should the temperature difference be between the box temperature and the boiling point temperature for a reach-in cooler? - Answer 10° to 20° F What is an indicator of air in a refrigeration system? - Answer High head pressure and the ambient temperature and saturation temperature are incompatible after a system pumpdown What type of valve is a heat reclaim valve? - Answer A 3-way hot gas valve Which amperage is higher, inrush or the operating amperage? - Answer Inrush Two capacitors wired in series, one 20 MFD and the other is 10 MFD, what's the total MFD? - Answer CT= 1 over 1/C¹ + 1/C² + ... When a three phase compressor operates with only two legs of power, this is known as: - Answer Single phasing What is the MFD with a 5 MFD in parallel with a 15 MFD capacitor? - Answer CT = C¹ + C² + ... Parallel