HVAC EXCELLENCE EXAM 500 QUESTIONS &
CORRECT ANSWERS LATEST 2025
A compressor that has a broken reed valve will cause these symptoms - ANSWER-
High suction pressure and low discharge pressure
Refrigerant r134a enters the condenser at 124 psig, 100 degrees F. It leaves as a
liquid from the condenser sub cooled 20 degrees And the pressure will be
approximately; - ANSWER-87 psig
Which is NOT a symptom of a hermetic compressor that is low on refrigerant? -
ANSWER-High head pressure
While troubleshooting a residential split system, the service technician finds low
operating pressures and low amperage. - ANSWER-Low airflow across evaporator
The automatic expansion valve is designed to maintain: - ANSWER-Constant
evaporator pressure
Which of the following is true of a solenoid valve in a pump down system? -
ANSWER-Its located before the metering device
A partially clogged capillary tube can cause - ANSWER-A starved evaporator
,An overcharge of refrigerant will cause - ANSWER-Increased head pressure
An increase in head pressure causes _____ refrigerant to flow through a capillary
tube. - ANSWER-More
A rise in evaporator pressure causes the automatic expansion valve to begin too
____. - ANSWER-Close
The oil separator is installed in the what? - ANSWER-Discharge line
The evaporator transfers - ANSWER-Heat from the refrigerated space to the
refrigerant
A partially iced over evaporator can be caused by - ANSWER-An undercharge
Water will vaporize at ____ temperature in a 28 hg vacuum. - ANSWER-100
degrees F
Zero psia - ANSWER-A pressure which cannot be further reduced
A TEV sensing bulb which becomes detached from the suction will cause these
symptoms - ANSWER-High suction pressure and higher than normal discharge
pressure
A refrigerant overcharge in a capillary tube system will cause these systems -
ANSWER-High suction pressure and high discharge pressure
,A liquid to suction heat exchanger is often used to - ANSWER-Increase liquid sub
cooling
In the evaporator _______ is transferred from the refrigerated space to the
refrigerant - ANSWER-Latent heat
With an automatic expansion valve, an increase in evaporator load will causes the
- ANSWER-Automatic expansion valve to open
Zero psig - ANSWER-The same as atmospheric pressure
decrease in superheat will make the thermal expansion valve begin - ANSWER-to
close
The sequential order of steps in in the vapor compression process are - ANSWER-
Compression condensation expansion vaporization
The state of refrigerant in the suction line should be - ANSWER-Low pressure low
temperature vapor
Bubbles in the sight glass could be an indication of - ANSWER-Low compressor
capacity
An inefficient compressor is usually indicates by _____ head pressure and
_______ suction line temperature - ANSWER-Lower than normal and higher than
normal
, Heat added to a substance without a rise in temp - ANSWER-Latent heat
When testing the efficiency of a water cooled condenser, the refrigerant
condensing temperature should be approximately _______ higher than the
leaving water temperature - ANSWER-10 degrees F
A faulty condenser fan motor will cause - ANSWER-High suction pressure and high
discharge pressure
A low pressure cut off switch is used too - ANSWER-Establish a minimum pressure
in the evaporator
A liquid line filter drier should be placed - ANSWER-Between condenser and
metering device
Low Refrigerant Charge will cause - ANSWER-Low suction pressure and low
discharge pressure
The thermostatic expansion valve is designed to maintain - ANSWER-constant
evaporator superheat
A sight glass would normally be located - ANSWER-In the liquid line, before the
metering device
A dirty evaporator will cause - ANSWER-Low suction pressure and low discharge
pressure
CORRECT ANSWERS LATEST 2025
A compressor that has a broken reed valve will cause these symptoms - ANSWER-
High suction pressure and low discharge pressure
Refrigerant r134a enters the condenser at 124 psig, 100 degrees F. It leaves as a
liquid from the condenser sub cooled 20 degrees And the pressure will be
approximately; - ANSWER-87 psig
Which is NOT a symptom of a hermetic compressor that is low on refrigerant? -
ANSWER-High head pressure
While troubleshooting a residential split system, the service technician finds low
operating pressures and low amperage. - ANSWER-Low airflow across evaporator
The automatic expansion valve is designed to maintain: - ANSWER-Constant
evaporator pressure
Which of the following is true of a solenoid valve in a pump down system? -
ANSWER-Its located before the metering device
A partially clogged capillary tube can cause - ANSWER-A starved evaporator
,An overcharge of refrigerant will cause - ANSWER-Increased head pressure
An increase in head pressure causes _____ refrigerant to flow through a capillary
tube. - ANSWER-More
A rise in evaporator pressure causes the automatic expansion valve to begin too
____. - ANSWER-Close
The oil separator is installed in the what? - ANSWER-Discharge line
The evaporator transfers - ANSWER-Heat from the refrigerated space to the
refrigerant
A partially iced over evaporator can be caused by - ANSWER-An undercharge
Water will vaporize at ____ temperature in a 28 hg vacuum. - ANSWER-100
degrees F
Zero psia - ANSWER-A pressure which cannot be further reduced
A TEV sensing bulb which becomes detached from the suction will cause these
symptoms - ANSWER-High suction pressure and higher than normal discharge
pressure
A refrigerant overcharge in a capillary tube system will cause these systems -
ANSWER-High suction pressure and high discharge pressure
,A liquid to suction heat exchanger is often used to - ANSWER-Increase liquid sub
cooling
In the evaporator _______ is transferred from the refrigerated space to the
refrigerant - ANSWER-Latent heat
With an automatic expansion valve, an increase in evaporator load will causes the
- ANSWER-Automatic expansion valve to open
Zero psig - ANSWER-The same as atmospheric pressure
decrease in superheat will make the thermal expansion valve begin - ANSWER-to
close
The sequential order of steps in in the vapor compression process are - ANSWER-
Compression condensation expansion vaporization
The state of refrigerant in the suction line should be - ANSWER-Low pressure low
temperature vapor
Bubbles in the sight glass could be an indication of - ANSWER-Low compressor
capacity
An inefficient compressor is usually indicates by _____ head pressure and
_______ suction line temperature - ANSWER-Lower than normal and higher than
normal
, Heat added to a substance without a rise in temp - ANSWER-Latent heat
When testing the efficiency of a water cooled condenser, the refrigerant
condensing temperature should be approximately _______ higher than the
leaving water temperature - ANSWER-10 degrees F
A faulty condenser fan motor will cause - ANSWER-High suction pressure and high
discharge pressure
A low pressure cut off switch is used too - ANSWER-Establish a minimum pressure
in the evaporator
A liquid line filter drier should be placed - ANSWER-Between condenser and
metering device
Low Refrigerant Charge will cause - ANSWER-Low suction pressure and low
discharge pressure
The thermostatic expansion valve is designed to maintain - ANSWER-constant
evaporator superheat
A sight glass would normally be located - ANSWER-In the liquid line, before the
metering device
A dirty evaporator will cause - ANSWER-Low suction pressure and low discharge
pressure
