Ac Certification Questions With Correct Answers.

Heat which can cause a change in temperature of a substance is called; - Sensible Heat Heat added to a substance without a rise in temperature;(example: liquid refrigerant to gas) this process is called? - Latent Heat of Vaporization Heat added to the refrigerant in a vapor state after the evaporation process is called; - Superheat A scroll compressor move refrigerant by means of; - Involute spirals The movement of heat by way of fluid(of air) is called; - Convection The movement of heat through a solid object is called; - Conduction The standard unit for measuring the quantity of heat in a substance is; - The British Thermal Unit(Btu) A refrigerant gives up heat when; - it Condenses Why must refrigerant in the suction line be slightly warmer than the saturation temperature? - Prevent liquid slugging of the compressor The state of the refrigerant entering the condenser is; - High pressure/highly superheated vapor The evaporator; - Transfers heat from the refrigerated space to the refrigerant Which of the following is NOT a thermodynamic property of refrigerants? - FlammabilityThe state of the refrigerant in the suction line should be; - Low pressure/low temperature liquid The sequential order of steps in the vapor-compression process are; - compression,condensation, expansion, vaporization If a 30 pound cylinder of reclaimed R-410A refrigerant has been stored overnight at 70F, the pressure ain the cylinder should be approximately; - 201psig Fan airflow pressures are usually measured in; - Inches of water column(WC) Zero psia(pounds per square inch absolute) is; - A pressure which cannot be further reduced Zero psig(pounds per square inch gauge)is; - The same as atmospheric pressure The temperature at which moisture will start to condensate from the air is called; - Dew point temperature A compound pressure and gauge measures; - Pressure and vaccum A mechanical shaft seal is necessary on a; - Open drive compressor Liquid slugging is; - Liquid refrigerant in the compressor clearance space The clearance space in a reciprocating compressor - Has an effect on compressor capacity Which of the following types of air conditioning compressors is most energy efficient? - Scroll Which of the following represents the right order for the functions of a condenser? - DeSuperheat, Condenses, Sub-CoolsRefrigerant R-134a vapor enters the condenser at 124 PSIG, 100F. It leaves as a liquid from the condenser sub-cooled 20F. The pressure will approximately be - 87 PSIG There are theee basic types of condensers, the air cooled, the water cooled, and the_________cooled. - evaporative 10 lbs of refrigerant passing through a water cooled condenser will lose 20 Btu's of heat per lb. If 10 lbs of water passes through the condenser with an entering temperature of 80F. The temperature of the water leaving the condenser is; - 100F The heat removed from the refrigerant by the condenser is; - Both Sensible and Latent heat An Energy Recovery Ventilator is; - An air to air heat exchanger to recover heat When testing the efficiency of an air cooled condenser, the refrigerant condensing temperature should be approximately____higher than the entering air temperature - 30F