NATE Exam: Air Conditioning and Heat Pumps –
Questions & Answers
Which of the following factors affects a customer's level of comfort?
a. Air movement
b. Humidity
c. Temperature
d. All of the above Correct Answer - d (All of the above: air movement,
humidity, temperature)
A cooling load calculation estimates the sensible heat gain of a structure. The
maximum sensible capacity of a cooling-only system should be within ____% of
this calculated value.
a. ±10%
b. +10%
c. +15%
d. +30% Correct Answer - c (+15%)
The maximum sensible cooling capacity of a heat pump should be within ____
% of the calculated sensible heat gain of a structure with a large heating load.
a. ±10%
b. +15%
c. -25%
d. +25% Correct Answer - d (+25%)
The combined output of a heat pump and its auxiliary heat should not exceed
the calculated heat loss of a home by more than ____%.
a. 10%
b. 15%
c. 20%
d. 25% Correct Answer - b (15%)
,What amount of auxiliary electric heat is needed when the output of a heat
pump on a design day equals 18,800 Btuh and the heat loss of a home is
29,700 Btuh?
a. 2.1 kWh
b. 3.2 kWh
c. 5.0 kWh
d. 10.9 kWh
Note: 3,413 Btu/kW Correct Answer - b (3.2 kWh)
The three processes that transfer heat energy are conduction, convection, and
____.
a. concentration
b. radiation
c. refraction
d. static pressure Correct Answer - b (radiation)
Heat transfer that occurs when substances of different temperatures are in
contact with each other is called ____.
a. concentration
b. conduction
c. convection
d. radiation Correct Answer - b (conduction)
What effect does raising the pressure in a sealed system have on refrigerant?
a. It becomes more difficult to subcool the liquid refrigerant
b. It becomes more difficult to superheat the refrigerant vapor
c. The refrigerant's boiling point decreases
d. The refrigerant's boiling point increases Correct Answer - d (The
refrigerant's boiling point increases)
What is the primary danger to people near an accidental refrigerant release or
spill?
, a. Blurred vision caused by the refrigerant vapor coming in contact with the
eyes
b. Changes in weather patterns caused by global warming
c. Damage to the food chain caused by decreased ozone levels in the
stratosphere
d. Suffocation caused by the heavier refrigerant displacing oxygen in the air
Correct Answer - d (Suffocation caused by the heavier refrigerant
displacing oxygen in the air)
The maximum temperature at which refrigerant may be stored is ____°F when
the container is no more than ____% full of liquid by volume.
a. 120°F, 60%
b. 125°F, 60%
c. 125°F, 80%
d. 135°F, 80% Correct Answer - c (125°F, 80%)
Boiling of the refrigerant occurs in which system component?
a. Compressor
b. Condenser
c. Evaporator
d. Metering device Correct Answer - c (Evaporator)
Why is superheat necessary in a system that utilizes hermetic compressors?
a. It ensures that dry vapor reaches the compressor so that mechanical
damage does not occur
b. It increases system capacity
c. It prevents liquid refrigerant from gassing the metering device
d. Superheat is necessary only when open compressors are being used
Correct Answer - a (It ensures that dry vapor reaches the compressor so
that mechanical damage does not occur)
When the heat load on an evaporator increases, what is the effect on the
system?
a. Suction pressure decreases and discharge pressure increases
b. Suction pressure increases and discharge pressure decreases
Questions & Answers
Which of the following factors affects a customer's level of comfort?
a. Air movement
b. Humidity
c. Temperature
d. All of the above Correct Answer - d (All of the above: air movement,
humidity, temperature)
A cooling load calculation estimates the sensible heat gain of a structure. The
maximum sensible capacity of a cooling-only system should be within ____% of
this calculated value.
a. ±10%
b. +10%
c. +15%
d. +30% Correct Answer - c (+15%)
The maximum sensible cooling capacity of a heat pump should be within ____
% of the calculated sensible heat gain of a structure with a large heating load.
a. ±10%
b. +15%
c. -25%
d. +25% Correct Answer - d (+25%)
The combined output of a heat pump and its auxiliary heat should not exceed
the calculated heat loss of a home by more than ____%.
a. 10%
b. 15%
c. 20%
d. 25% Correct Answer - b (15%)
,What amount of auxiliary electric heat is needed when the output of a heat
pump on a design day equals 18,800 Btuh and the heat loss of a home is
29,700 Btuh?
a. 2.1 kWh
b. 3.2 kWh
c. 5.0 kWh
d. 10.9 kWh
Note: 3,413 Btu/kW Correct Answer - b (3.2 kWh)
The three processes that transfer heat energy are conduction, convection, and
____.
a. concentration
b. radiation
c. refraction
d. static pressure Correct Answer - b (radiation)
Heat transfer that occurs when substances of different temperatures are in
contact with each other is called ____.
a. concentration
b. conduction
c. convection
d. radiation Correct Answer - b (conduction)
What effect does raising the pressure in a sealed system have on refrigerant?
a. It becomes more difficult to subcool the liquid refrigerant
b. It becomes more difficult to superheat the refrigerant vapor
c. The refrigerant's boiling point decreases
d. The refrigerant's boiling point increases Correct Answer - d (The
refrigerant's boiling point increases)
What is the primary danger to people near an accidental refrigerant release or
spill?
, a. Blurred vision caused by the refrigerant vapor coming in contact with the
eyes
b. Changes in weather patterns caused by global warming
c. Damage to the food chain caused by decreased ozone levels in the
stratosphere
d. Suffocation caused by the heavier refrigerant displacing oxygen in the air
Correct Answer - d (Suffocation caused by the heavier refrigerant
displacing oxygen in the air)
The maximum temperature at which refrigerant may be stored is ____°F when
the container is no more than ____% full of liquid by volume.
a. 120°F, 60%
b. 125°F, 60%
c. 125°F, 80%
d. 135°F, 80% Correct Answer - c (125°F, 80%)
Boiling of the refrigerant occurs in which system component?
a. Compressor
b. Condenser
c. Evaporator
d. Metering device Correct Answer - c (Evaporator)
Why is superheat necessary in a system that utilizes hermetic compressors?
a. It ensures that dry vapor reaches the compressor so that mechanical
damage does not occur
b. It increases system capacity
c. It prevents liquid refrigerant from gassing the metering device
d. Superheat is necessary only when open compressors are being used
Correct Answer - a (It ensures that dry vapor reaches the compressor so
that mechanical damage does not occur)
When the heat load on an evaporator increases, what is the effect on the
system?
a. Suction pressure decreases and discharge pressure increases
b. Suction pressure increases and discharge pressure decreases
