NCCER Module 5 Introduction to cooling correctly answered to pass 2023/2024

NCCER Module 5 Introduction to cooling The Celsius scale is based on boiling water having a temperature at sea level of_? 100° Subcooling occurs_. After all vapor has changed to liquid When the temperature of a vapor is higher than its boiling point, the vapor is_? Superheated When heat is carried from one object to another by means of a moving liquid or gas, it is being transferred by_? Convection A ton of refrigeration is equal to_? 12,000 BTUs per hour When the pressure on a liquid in a closed space is increased, what happens to the boiling point? It raises the boiling point In a refrigeration system, the high-pressure, high temperature vapor is converted into a high pressure, high temperature liquid by the_? Condenser Most all of today's standard refrigerant gauge manifold have a high pressure gauge that goes up to_? 800 psig The substance in refrigerant that is primarily responsible for damaging the O-Zone layer is_? Chlorine Which of the following statements about refrigerant mixtures is correct? When a leak develops, more of one refrigerant may leak out then the other refrigerants Which of the following statements about ammonia is true? Ammonia piping cannot be constructed from copper The net weight of a refrigerant cylinder is the_? Weight of the contents alone The construction and labeling of refrigerant containers is governed by_? the DOT In a semi hermetic compressor,_? The compressor and drive motor share a common housing Which type of compressor is typically used only in systems needing 100 tons of capacity or more? Centrifugal Which type of condenser is generally used only with small domestic refrigeration systems? Plate For an evaporator to operate a peek efficiency,_? All of the surface area inside the tubes must be exposed to flashing liquid One of the advantages of a fixed metering device is_? It's low cost Which of the following metering devices response to changes in the superheat of the refrigerant vapor leaving the evaporator? Thermostatic expansion valve What refrigerant piping technique helps to get oil to flow up a suction line riser along with vapor? Installing a trap at the bottom of the riser The device installed to prevent liquid refrigerant from returning to the compressor crank case during system operation is the_? Suction line accumulator To close a control circuit and start a system a remote bulb thermostat depends on a_? Refrigerant filled bulb that response to temperature changes Which of the following control devices is often used in both a primary and a secondary control roll? Pressure switches Immaterial that readily and actively absorbs water is considered_? Hygroscopic A device used to prevent the reverse flow of a liquid is a_? Check valve