HVAC HEATING TEST QUESTIONS AND ANSWERS
On a central gas furnace, which of the following conditions would cause the high limit
control to open circuit ? - Answers :Fan contol is open
After replacing the compressor in a heat pump during the heating season, a technician
must charge the system to the proper lvl. Which is the most accurate method ? -
Answers :Weigh in the exact charge
A situation in which the flame on a gas furnace continually rolls out could be caused by -
Answers :A plugged heater exchange
On heat pumps using a liquid line temperature sensing device for the terminating
defrost cycles, which causes device to terminate defrost - Answers :Increase in the
temperate of the liquid line
In a duct system, where should vibration eliminators be placed ? - Answers :Between air
handler and first duct
An increase in the latent heat load across the evaporator will cause which of the
following changes: - Answers :An increase in evaporator and condenser pressure
The normal indoor airflow through a heat pump or air conditioner should be
approximately - Answers :400 cfm/ton
With an oil gun burner, atomized oil is ignited by an: - Answers :Electrics arc between
electrodes
To check if a fixed resistance crankcase heater is operating with power applied, you
would normally use - Answers :An ammeter
Which of the following is the most probable cause of a high discharge pressures in a
cooling system ? - Answers :Dirty condenser coil
Commonly specified manufacturers requirements for the venting of 90+ high efficiency
furnaces are sized for vent, number of elbows, venting materials? And: - Answers
:Length of vent
The most important advantage of using brazing alloys with a higher silver content is that
? - Answers :The joint is stronger
On split system air conditioner, increasing the air flow through an evaporator : -
Answers :Will cause frost to build up on coil
, Step opening gas baubles can be described as valves that open - Answers :At partial
rate, then change to full rate
Which indicated a possible system overcharge on an air conditioner with a fixed orifice
Kettering device? - Answers :Head high, high suction pressure
A correct statement regarding the fan/limit controller is that it senses the: - Answers
:Supply air temperature in the furnace
A correct statement regarding suction line filter driers is that they should be used when:
- Answers :Replacing a compressor after a burnout
The component that is installed on the low since to prevent liquid from entering the
compressor is called an : - Answers :Accumulator
The reason many residents are not equipped to take in fresh air through duct system is
because : - Answers :Infiltration is used to meet the need for fresh air
In a natural draft gas- fired furnace, most probable cause of the flame lifting off the
burner is: - Answers :Too much gas pressure
For proper burner operation, the manifold pressure on atmospheric draft natural gas-
fires furnaces should be: - Answers :3-4 inches of water
The purpose of sequencer replays in an electric warm-air heating system is to: -
Answers :Prevent all elements from being energized at same times
Which of the following is the primary purpose of a low-ambient control - Answers
:Maintain minimum discharge pressure
Which of the following measurements are needed to determine superheat ? - Answers
:Suction line pressure and temperature
On a "no heat call" what precautions must technician take before touching furnace ? -
Answers :Check the combustion chamber for liquid oil
Which of the following measurements would be needed to determine oil furnace
combustion efficiency? - Answers :Bet stack temperature and CO2
For systems hard drawn copper tubing, which of the following should be used to
fabricate a 90 degree bend ? - Answers :A 90 degree elbow, long radius
When refrigerant is being recovered from a system under repair, recovery should be
filled to max of: - Answers :80% of its rated capacity
On a central gas furnace, which of the following conditions would cause the high limit
control to open circuit ? - Answers :Fan contol is open
After replacing the compressor in a heat pump during the heating season, a technician
must charge the system to the proper lvl. Which is the most accurate method ? -
Answers :Weigh in the exact charge
A situation in which the flame on a gas furnace continually rolls out could be caused by -
Answers :A plugged heater exchange
On heat pumps using a liquid line temperature sensing device for the terminating
defrost cycles, which causes device to terminate defrost - Answers :Increase in the
temperate of the liquid line
In a duct system, where should vibration eliminators be placed ? - Answers :Between air
handler and first duct
An increase in the latent heat load across the evaporator will cause which of the
following changes: - Answers :An increase in evaporator and condenser pressure
The normal indoor airflow through a heat pump or air conditioner should be
approximately - Answers :400 cfm/ton
With an oil gun burner, atomized oil is ignited by an: - Answers :Electrics arc between
electrodes
To check if a fixed resistance crankcase heater is operating with power applied, you
would normally use - Answers :An ammeter
Which of the following is the most probable cause of a high discharge pressures in a
cooling system ? - Answers :Dirty condenser coil
Commonly specified manufacturers requirements for the venting of 90+ high efficiency
furnaces are sized for vent, number of elbows, venting materials? And: - Answers
:Length of vent
The most important advantage of using brazing alloys with a higher silver content is that
? - Answers :The joint is stronger
On split system air conditioner, increasing the air flow through an evaporator : -
Answers :Will cause frost to build up on coil
, Step opening gas baubles can be described as valves that open - Answers :At partial
rate, then change to full rate
Which indicated a possible system overcharge on an air conditioner with a fixed orifice
Kettering device? - Answers :Head high, high suction pressure
A correct statement regarding the fan/limit controller is that it senses the: - Answers
:Supply air temperature in the furnace
A correct statement regarding suction line filter driers is that they should be used when:
- Answers :Replacing a compressor after a burnout
The component that is installed on the low since to prevent liquid from entering the
compressor is called an : - Answers :Accumulator
The reason many residents are not equipped to take in fresh air through duct system is
because : - Answers :Infiltration is used to meet the need for fresh air
In a natural draft gas- fired furnace, most probable cause of the flame lifting off the
burner is: - Answers :Too much gas pressure
For proper burner operation, the manifold pressure on atmospheric draft natural gas-
fires furnaces should be: - Answers :3-4 inches of water
The purpose of sequencer replays in an electric warm-air heating system is to: -
Answers :Prevent all elements from being energized at same times
Which of the following is the primary purpose of a low-ambient control - Answers
:Maintain minimum discharge pressure
Which of the following measurements are needed to determine superheat ? - Answers
:Suction line pressure and temperature
On a "no heat call" what precautions must technician take before touching furnace ? -
Answers :Check the combustion chamber for liquid oil
Which of the following measurements would be needed to determine oil furnace
combustion efficiency? - Answers :Bet stack temperature and CO2
For systems hard drawn copper tubing, which of the following should be used to
fabricate a 90 degree bend ? - Answers :A 90 degree elbow, long radius
When refrigerant is being recovered from a system under repair, recovery should be
filled to max of: - Answers :80% of its rated capacity
