NATE Light Commercial Refrigeration Questions And Answers, Exams of Advanced Education

Download NATE Light Commercial Refrigeration Questions And Answers and more Exams Advanced Education in PDF only on Docsity! NATE Light Commercial Refrigeration What is the MOST important aspect about installing a rooftop package unit? - The roof will support the weight What could be at fault of an air cooled system that operates 50°F over ambient temperature? - An overcharge, air in the system, or air re-circulating over the condenser Where should the sensing bulb on a TXV be located? - 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 ____________ - In phase with each other If a single phase compressor is cycling on its overload protector, what should be checked? - Voltage input, test capacitors, start relays, and motor windings. What is the maximum pressure drop across an R-404A suction line filter dryer? - 2 PSI (2 degree saturation temp) What type of maintenance do water cooled condensers require? - 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? - A faulty run capacitor What causes excessive head pressure on water cooled condensers? - Fouled condenser water, dirty water cooled condenser, over charge and air trapped in the condenser What happens during a hot pull down? - 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? - A plugged drain line or a defective drain pan heater Name some ways to maintain head pressure during low ambient conditions - 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? - 10° to 20° F