HVAC EXCELLENCE COMPREHENSIVE EXAM QUESTIONS
AND ANSWERS RATED A+
✔✔Which of the following represnet the right order for the functionsof a condenser -
✔✔De-Superheats, Condenses, and Sub-cools
✔✔Refrigerant R-134a vapor enters the condenser at 124psig, 100 degrees faranheit, It
leaves as a liquid from the condenser, sub-cooled 20 degrees faranheit, and the
pressure will be approximately - ✔✔124 psig
✔✔There are 3 basic types of condensers, air cooled, water cooled, and -
✔✔evaporative cooled
✔✔10 lbs of refrigerant passing through a water cooled condenser will lose 20 BTU of
heat/ pound. If 10#'s of water passes through the condenser with an entering temp of 80
degrees, the temp of the water leaving the condenser is - ✔✔100 degrees faranheit
✔✔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 exhanger to recover heat
✔✔Which of hte following can not be used as a low ambient temperature control? -
✔✔Crankcase regulating valves
✔✔When testing the efficiency of an air cooled condenser, the refrigerant condensing
temperature should be no more than _____ higher than the entering air temp. - ✔✔30
degrees
✔✔The First function a condenser must perform is to ___ the refrigerant before
condesing can occur. - ✔✔De-Superheat
✔✔A thermostatic expansion valve is designed to maintain - ✔✔Constant evaporator
superheat
✔✔The thermostatic expansion valve has three operating pressures - ✔✔Evaporator,
Spring and Sensing bulb Pressure
✔✔When Mounting a thermostatic expansion valve sensor bulb, which of the folling is
NOT true? - ✔✔It must be installed lower than the valve body
, ✔✔In an air conditioning system that uses a thermostatic expansion valve, the
temperature of the evaporator outlet will usually be: - ✔✔Warmer than the evaporator
inlet
✔✔An automatic expansion valve is best suited: - ✔✔When the system load remains
fairly constant
✔✔Which of the following is not true of a capillary tube metering device? - ✔✔They
maintain a constant evaporator temperature
✔✔A decrease in superheat causes the thermostatic expansion valve to - ✔✔Close
✔✔A rise in evaporator pressure causes the automatic expansion valve to begin to -
✔✔close
✔✔a thermal-electric ( solid state) expansion valveis controlled by - ✔✔NTC Thermistor
✔✔In a Direct expansion (DX) evaporator system, the refrigerant enters the evaporator
as - ✔✔a mixture of liquid with some "flash gas"
✔✔In the Evaporator - ✔✔Latent heat is transferred from the refrigerated space to the
refrigerant
✔✔A Liquid line filter drier should be placed between the - ✔✔Condenser and metering
device
✔✔The only way to minimize flash gas is by - ✔✔sub-cooling the liquid refrigerant
entering the metering device closer to the evaporator temperature
✔✔A liquid reciever is used to - ✔✔Store liquid refrigerant
✔✔An accumulator is used to - ✔✔Prevent liquid refrigerant from reaching the
compressor
✔✔A sight glass would normally be located - ✔✔in the liquied line, before the metering
device
✔✔Bubbles in the sight glass could be an indication of - ✔✔Low compressor capacity
✔✔The oil separator is installed in the - ✔✔Discharge line
✔✔Which of the following is true of a solenoid valve in a pump down system? - ✔✔It is
located before the metering device
AND ANSWERS RATED A+
✔✔Which of the following represnet the right order for the functionsof a condenser -
✔✔De-Superheats, Condenses, and Sub-cools
✔✔Refrigerant R-134a vapor enters the condenser at 124psig, 100 degrees faranheit, It
leaves as a liquid from the condenser, sub-cooled 20 degrees faranheit, and the
pressure will be approximately - ✔✔124 psig
✔✔There are 3 basic types of condensers, air cooled, water cooled, and -
✔✔evaporative cooled
✔✔10 lbs of refrigerant passing through a water cooled condenser will lose 20 BTU of
heat/ pound. If 10#'s of water passes through the condenser with an entering temp of 80
degrees, the temp of the water leaving the condenser is - ✔✔100 degrees faranheit
✔✔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 exhanger to recover heat
✔✔Which of hte following can not be used as a low ambient temperature control? -
✔✔Crankcase regulating valves
✔✔When testing the efficiency of an air cooled condenser, the refrigerant condensing
temperature should be no more than _____ higher than the entering air temp. - ✔✔30
degrees
✔✔The First function a condenser must perform is to ___ the refrigerant before
condesing can occur. - ✔✔De-Superheat
✔✔A thermostatic expansion valve is designed to maintain - ✔✔Constant evaporator
superheat
✔✔The thermostatic expansion valve has three operating pressures - ✔✔Evaporator,
Spring and Sensing bulb Pressure
✔✔When Mounting a thermostatic expansion valve sensor bulb, which of the folling is
NOT true? - ✔✔It must be installed lower than the valve body
, ✔✔In an air conditioning system that uses a thermostatic expansion valve, the
temperature of the evaporator outlet will usually be: - ✔✔Warmer than the evaporator
inlet
✔✔An automatic expansion valve is best suited: - ✔✔When the system load remains
fairly constant
✔✔Which of the following is not true of a capillary tube metering device? - ✔✔They
maintain a constant evaporator temperature
✔✔A decrease in superheat causes the thermostatic expansion valve to - ✔✔Close
✔✔A rise in evaporator pressure causes the automatic expansion valve to begin to -
✔✔close
✔✔a thermal-electric ( solid state) expansion valveis controlled by - ✔✔NTC Thermistor
✔✔In a Direct expansion (DX) evaporator system, the refrigerant enters the evaporator
as - ✔✔a mixture of liquid with some "flash gas"
✔✔In the Evaporator - ✔✔Latent heat is transferred from the refrigerated space to the
refrigerant
✔✔A Liquid line filter drier should be placed between the - ✔✔Condenser and metering
device
✔✔The only way to minimize flash gas is by - ✔✔sub-cooling the liquid refrigerant
entering the metering device closer to the evaporator temperature
✔✔A liquid reciever is used to - ✔✔Store liquid refrigerant
✔✔An accumulator is used to - ✔✔Prevent liquid refrigerant from reaching the
compressor
✔✔A sight glass would normally be located - ✔✔in the liquied line, before the metering
device
✔✔Bubbles in the sight glass could be an indication of - ✔✔Low compressor capacity
✔✔The oil separator is installed in the - ✔✔Discharge line
✔✔Which of the following is true of a solenoid valve in a pump down system? - ✔✔It is
located before the metering device
