HVAC Test exam Verified Questions and
Correct Answers
What is the primary danger to people near an accidental refrigerant release or
spill: - ANSWER>>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 - ANSWER>>125 F /
80%
The effect of a low charge on the switchover operations of a. reversing valve is
the: - ANSWER>>Reversing valves are less likely to transfer if charge is low
On some installations, a heat pump indoor coil can be installed on an existing,
operable, fossil fuel furnace. When this type of installation is done, you need to
add a control so that: - ANSWER>>The furnace and heat pump do not operate at
the same time in normal heating
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
- ANSWER>>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 ____% - ANSWER>>15%
What amount of auxiliary electric heat is needed when the output of a heat pump
on a design day equals 18,800 Bruh and the heat loss of a home is 29,200 Btuh -
ANSWER>>3.2 kWh
,The three processes that transfer heat energy are conduction, convection, and -
ANSWER>>Radiation
Heat transfer that occurs when substances of different temperatures are in
contact with each other is called - ANSWER>>Conduction
What effect does raising the pressure in a sealed system has on refrigerant -
ANSWER>>The refrigerants boiling point increases
A simple time activated switch is an example of a control that does not use: -
ANSWER>>Feedback
Which of the following systems would typically require a blower with a 2000 cam
output: - ANSWER>>5 ton ac system
A typical induced-draft furnace uses a blower-off delay in the cooling mode to: -
ANSWER>>Increase the efficiency of the system
Wood studs in typical residential construction are how far apart: - ANSWER>>16
inches
The following component is energized first after an intermittent ignition gas
furnace calls for heat? - ANSWER>>Induced draft motor
The number 3,412 but is equal to - ANSWER>>1 Kilowatt
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: - ANSWER>>15%+
Undersized duct work will often cause: - ANSWER>>Noise, high static pressure,
and low volume
, Determine voltage drop at the outdoor unit requires: - ANSWER>>Checking
voltage feed with the outdoor unit not running and then with the outdoor unit
running
A manometer is used to: - ANSWER>>Measure static duct pressure
A system that has been evacuated to 500 microns and rises immediately and at a
constant rate after the vacuum pump has been shut off: - ANSWER>>Due to a
leak in a system
To obtain an accurate refrigerant temperature on a horizontal suction line that is
1 1/8" or larger: - ANSWER>>The TXV sensing bulb should be located at 4 or 8
inches o clock on the pipe
The primary consideration when bending soft copper to any radius is the: -
ANSWER>>Cross sectional area must not be significantly reduced
There are more circuits in a HP outdoor coil than in an A/C outdoor coil to: -
ANSWER>>Minimize refrigerant pressure drop
Inefficient voltage or current to a solenoid will result in: - ANSWER>>Vibration or
chatter of the solenoid
A compressor that is suspected to be grounded to its housing should be checked
for: - ANSWER>>Continuity from the terminal windings to ground
The coil of a potential relay is connected to: - ANSWER>>The common and start
terminals of a compressor
When the load on a HP in cooling mode decreases - ANSWER>>Suction pressure
increases and discharge pressure decreases
Correct Answers
What is the primary danger to people near an accidental refrigerant release or
spill: - ANSWER>>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 - ANSWER>>125 F /
80%
The effect of a low charge on the switchover operations of a. reversing valve is
the: - ANSWER>>Reversing valves are less likely to transfer if charge is low
On some installations, a heat pump indoor coil can be installed on an existing,
operable, fossil fuel furnace. When this type of installation is done, you need to
add a control so that: - ANSWER>>The furnace and heat pump do not operate at
the same time in normal heating
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
- ANSWER>>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 ____% - ANSWER>>15%
What amount of auxiliary electric heat is needed when the output of a heat pump
on a design day equals 18,800 Bruh and the heat loss of a home is 29,200 Btuh -
ANSWER>>3.2 kWh
,The three processes that transfer heat energy are conduction, convection, and -
ANSWER>>Radiation
Heat transfer that occurs when substances of different temperatures are in
contact with each other is called - ANSWER>>Conduction
What effect does raising the pressure in a sealed system has on refrigerant -
ANSWER>>The refrigerants boiling point increases
A simple time activated switch is an example of a control that does not use: -
ANSWER>>Feedback
Which of the following systems would typically require a blower with a 2000 cam
output: - ANSWER>>5 ton ac system
A typical induced-draft furnace uses a blower-off delay in the cooling mode to: -
ANSWER>>Increase the efficiency of the system
Wood studs in typical residential construction are how far apart: - ANSWER>>16
inches
The following component is energized first after an intermittent ignition gas
furnace calls for heat? - ANSWER>>Induced draft motor
The number 3,412 but is equal to - ANSWER>>1 Kilowatt
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: - ANSWER>>15%+
Undersized duct work will often cause: - ANSWER>>Noise, high static pressure,
and low volume
, Determine voltage drop at the outdoor unit requires: - ANSWER>>Checking
voltage feed with the outdoor unit not running and then with the outdoor unit
running
A manometer is used to: - ANSWER>>Measure static duct pressure
A system that has been evacuated to 500 microns and rises immediately and at a
constant rate after the vacuum pump has been shut off: - ANSWER>>Due to a
leak in a system
To obtain an accurate refrigerant temperature on a horizontal suction line that is
1 1/8" or larger: - ANSWER>>The TXV sensing bulb should be located at 4 or 8
inches o clock on the pipe
The primary consideration when bending soft copper to any radius is the: -
ANSWER>>Cross sectional area must not be significantly reduced
There are more circuits in a HP outdoor coil than in an A/C outdoor coil to: -
ANSWER>>Minimize refrigerant pressure drop
Inefficient voltage or current to a solenoid will result in: - ANSWER>>Vibration or
chatter of the solenoid
A compressor that is suspected to be grounded to its housing should be checked
for: - ANSWER>>Continuity from the terminal windings to ground
The coil of a potential relay is connected to: - ANSWER>>The common and start
terminals of a compressor
When the load on a HP in cooling mode decreases - ANSWER>>Suction pressure
increases and discharge pressure decreases
