HVAC EXCELLENCE EXAMS SCRIPT UPDATED EXAM
QUESTIONS AND SOLUTIONS RATED A+
✔✔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 80ºF. the temperature of the water leaving the condenser is? - ✔✔100ºF
✔✔Heat which causes a change in temperature of a substance is called? - ✔✔sensible
heat
✔✔A compound pressure gauge measures? - ✔✔pressure and vacuum
✔✔A liquid receiver is used to? - ✔✔store liquid refrigerant
✔✔An automatic expansion valve is best suited? - ✔✔when the system load remains
fairly constant
✔✔A dirty evaporator on an air conditioning system will cause these symptoms? -
✔✔low suction pressure and low discharge pressure
✔✔The thermostatic expansion valve has three operating pressures? - ✔✔evaporator
pressure, spring pressure, and sensor bulb pressure
✔✔The flow rate of a TEV used in R410a systems as compared to R22 systems is? -
✔✔approximately 15% greater
✔✔Which of the following types of air conditioning compressors is the most efficient? -
✔✔scroll
✔✔Which of the following can NOT be used as a low ambient temperature control? -
✔✔crankcase regulating valve
✔✔When mounting a thermostatic expansion valve sensor bulb, which of the following
is NOT true? - ✔✔it must be installed lower than the valve body
✔✔In a direct expansion (DX) evaporator system, the refrigerant enters the evaporator
as? - ✔✔a mix of liquid with some flash-gas
✔✔When an automatic expansion valve is used as a metering device, a low refrigerant
charge will cause? - ✔✔low superheat
✔✔The sequential order of steps in the vapor - compression process is? -
✔✔compression, condensation, expansion, vaporization
, ✔✔A faulty condenser fan motor on an air conditioning system will cause these
symptoms? - ✔✔high suction pressure and high discharge pressure
✔✔The main function of the condenser is to? - ✔✔remove heat from the refrigerant
✔✔If a 30 pound cylinder of reclaimed R-410a refrigerant has been stored over night at
70º F, the pressure in the cylinder should be approximately? - ✔✔201 psig
✔✔Moisture in a refrigeration system will cause? - ✔✔low head pressure
✔✔When testing the efficiency of an air cooled condenser, the refrigerant condensing
temperature should be no more than ______ higher than the entering air temperature. -
✔✔approximately 30ºF
✔✔What is the recommended residential indoor relative humidity for summer? -
✔✔50%
✔✔Heat can travel by? - ✔✔conduction, convection, and radiation
✔✔If the cut-off plate is removed from a blower assembly, how would this effect blower
performance? - ✔✔it would reduce air flow
✔✔Solid contaminants, such as sludge and carbon, from a severe hermetic compressor
motor burn out are best removed? - ✔✔by flushing the system and then installing filter
driers in both the liquid and suction lines
✔✔A customer complains that their air conditioning system is running constantly, but
not cooling enough. The suction line is very cold and the compressor is sweating. The
most likely cause is? - ✔✔a restriction of the return air filter or dirty evaporator
✔✔A automatic expansion valve is designed to maintain? - ✔✔constant evaporator
pressure
✔✔Which of the following is the most important consideration in the selection of an
evaporator coil? Match the coil to the? - ✔✔condensing unit and the latent/sensible
loads
✔✔A mechanical shaft seal is necessary on a? - ✔✔open drive compressor
✔✔Liquid slugging is? - ✔✔liquid refrigerant in the compressor clearance space
✔✔Water will vaporize at _______ temperature in a 28 in Hg vacuum? - ✔✔100ºF
QUESTIONS AND SOLUTIONS RATED A+
✔✔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 80ºF. the temperature of the water leaving the condenser is? - ✔✔100ºF
✔✔Heat which causes a change in temperature of a substance is called? - ✔✔sensible
heat
✔✔A compound pressure gauge measures? - ✔✔pressure and vacuum
✔✔A liquid receiver is used to? - ✔✔store liquid refrigerant
✔✔An automatic expansion valve is best suited? - ✔✔when the system load remains
fairly constant
✔✔A dirty evaporator on an air conditioning system will cause these symptoms? -
✔✔low suction pressure and low discharge pressure
✔✔The thermostatic expansion valve has three operating pressures? - ✔✔evaporator
pressure, spring pressure, and sensor bulb pressure
✔✔The flow rate of a TEV used in R410a systems as compared to R22 systems is? -
✔✔approximately 15% greater
✔✔Which of the following types of air conditioning compressors is the most efficient? -
✔✔scroll
✔✔Which of the following can NOT be used as a low ambient temperature control? -
✔✔crankcase regulating valve
✔✔When mounting a thermostatic expansion valve sensor bulb, which of the following
is NOT true? - ✔✔it must be installed lower than the valve body
✔✔In a direct expansion (DX) evaporator system, the refrigerant enters the evaporator
as? - ✔✔a mix of liquid with some flash-gas
✔✔When an automatic expansion valve is used as a metering device, a low refrigerant
charge will cause? - ✔✔low superheat
✔✔The sequential order of steps in the vapor - compression process is? -
✔✔compression, condensation, expansion, vaporization
, ✔✔A faulty condenser fan motor on an air conditioning system will cause these
symptoms? - ✔✔high suction pressure and high discharge pressure
✔✔The main function of the condenser is to? - ✔✔remove heat from the refrigerant
✔✔If a 30 pound cylinder of reclaimed R-410a refrigerant has been stored over night at
70º F, the pressure in the cylinder should be approximately? - ✔✔201 psig
✔✔Moisture in a refrigeration system will cause? - ✔✔low head pressure
✔✔When testing the efficiency of an air cooled condenser, the refrigerant condensing
temperature should be no more than ______ higher than the entering air temperature. -
✔✔approximately 30ºF
✔✔What is the recommended residential indoor relative humidity for summer? -
✔✔50%
✔✔Heat can travel by? - ✔✔conduction, convection, and radiation
✔✔If the cut-off plate is removed from a blower assembly, how would this effect blower
performance? - ✔✔it would reduce air flow
✔✔Solid contaminants, such as sludge and carbon, from a severe hermetic compressor
motor burn out are best removed? - ✔✔by flushing the system and then installing filter
driers in both the liquid and suction lines
✔✔A customer complains that their air conditioning system is running constantly, but
not cooling enough. The suction line is very cold and the compressor is sweating. The
most likely cause is? - ✔✔a restriction of the return air filter or dirty evaporator
✔✔A automatic expansion valve is designed to maintain? - ✔✔constant evaporator
pressure
✔✔Which of the following is the most important consideration in the selection of an
evaporator coil? Match the coil to the? - ✔✔condensing unit and the latent/sensible
loads
✔✔A mechanical shaft seal is necessary on a? - ✔✔open drive compressor
✔✔Liquid slugging is? - ✔✔liquid refrigerant in the compressor clearance space
✔✔Water will vaporize at _______ temperature in a 28 in Hg vacuum? - ✔✔100ºF
