Arizona HVAC Exam Review | C-39 Air Conditioning & Refrigeration Practice Questions, Answers & Licensing Prep 2026-2027
The position of the potential relay while the compressor is Open
running is....
Appliances located in a parking garage (commercial) shall 8 ft.
be located a minimum of _______ above the floor
Ducts connecting to a furnace shall have a minimum Or per manufacturer's installation instructions
clearance to combustibles....
A 12in x 12in. Square duct is being replaced with a round 13.11 in
duct. What size round duct will be needed to maintain the
same volume?
Round equivalent of an oval airway:
D = 1.3 x (144) 0.625/ 24^0.250
1.3 x 10.09 =
What controls the oil pump on an oil fired hydronic boiler? Thermostat
A secondary drain system shall do all of the following Not go over the main structure entrance
except:
An air handler located inside controls a condenser located Overhang roof under 8ft.
outside, what is not permitted?
What is a result of a steambound boiler? Underfilled Boiler
What is the purpose of a bleed-off device in a cooling To keep the evaportating water system clean
tower?
What is the maximum bend arc for steel gas piping 90 degrees
What is the purpose of an evaporator pressure regulator? Maintains a set minimum Pressure
What type of instrument is used to measure humidity Hygrometer
If an existing wall is rated at R-8 and new insulation is 0.4
added of R-15, what is the new U-Valve?
U-Value = 1/(sum of all R-Value)
What is the principle difference between a heat pump and Reversing Valve
a unit used for cooling only?
,Arizona HVAC Exam Review | C-39 Air Conditioning & Refrigeration Practice Questions, Answers & Licensing Prep 2026-2027
Which device prevents oil slugging? Crankcase Heater
What device is used to prevent slugging in a heat pump? Accumulators
When can a duct penetrate a fire wall? When protected with a listed fire damper
How often should the low water fuel shutoff shutoff should Daily
be tested using the blowdown method
What maximum temperature may a refrigerant cylinder be 120 *F
safely heated to in order to speed up the charging
process?
What limits the temperature of a burner? High Limit Control
The highest temperature at which a substance may be Critical Temperature
liquefied
What setting should the fuel gas valve be set for the Per Manufacturer
boiler?
What minimum size screen mesh should cover a 1/4 inch
combustion air inlet?
What happens when insulation gets wet? Reduces Heat - Insulation Qualities
Which of the following gases are not permitted for use in Oxygen
the testing of fuel gas systems?
What is the boiling point of R-134a at atmospheric -14.9 *F
pressure?
On Low Pressure Steam Systems and hot water boilers, Aluminum Shall NOT BE USED
which of the following material shall not be used?
Maximum spacing for hangers for horizontal steel pipe on 12 Feet
a hydronic system is?
All of the following are true of a chilled water system They are used primarily in residential systems
except
, Arizona HVAC Exam Review | C-39 Air Conditioning & Refrigeration Practice Questions, Answers & Licensing Prep 2026-2027
Repeated bending off soft copper tubing may cause it to Work Hardened
become
What is the maximum smoke developed rating of foam Smoke developed index of 450 or less
plastic insulation
In a hermetically sealed system, the oil in the crankcase is Winding Insulation Failure
tested and found to be acidic, what could be the cause or
source of this?
The minimum ID size for a fuel oil return line is 1/4 in. ID
Gas piping can be installed underground beneath a if installed in a conduit.
building:
The condensate line on a air conditioner can not drain by Drain Pump
gravity a ________ must be used to remove the
condensate to the outdoors
What does the potential relay do when energized? Disengaged the start capacitor
A furnace, located on a roof shall be installed on a 3 in 12
substantial level platform, when the roof has a slope of
_________ or greater, a level working platform, at least
30inches in an dimension shall be provided along the
firebox and control sides of the furnace
In a gas furnace, a yellow tipped flame indicates: Too little primary air
What is the minimum outside air required for a residential 2 .75 cfm/ sq ft
car garage
In a conventional wood frame construction, 2x6 nominal 1 3/8 inches
size wood studs in exterior walls and bearing partitions,
maybe be cut or notched to a maximum depth of
What types of controls are found on an HVAC system Electric, Pneumatic, Electronic
What is the minimum AFUE (Annual Fuel Utilization 78%
Efficiency) rating in a furnace?
How often must the relief valve on a low pressure boiler be Monthly
inspected?
How is the low water fuel shutoff tested? Blowdown Test
The position of the potential relay while the compressor is Open
running is....
Appliances located in a parking garage (commercial) shall 8 ft.
be located a minimum of _______ above the floor
Ducts connecting to a furnace shall have a minimum Or per manufacturer's installation instructions
clearance to combustibles....
A 12in x 12in. Square duct is being replaced with a round 13.11 in
duct. What size round duct will be needed to maintain the
same volume?
Round equivalent of an oval airway:
D = 1.3 x (144) 0.625/ 24^0.250
1.3 x 10.09 =
What controls the oil pump on an oil fired hydronic boiler? Thermostat
A secondary drain system shall do all of the following Not go over the main structure entrance
except:
An air handler located inside controls a condenser located Overhang roof under 8ft.
outside, what is not permitted?
What is a result of a steambound boiler? Underfilled Boiler
What is the purpose of a bleed-off device in a cooling To keep the evaportating water system clean
tower?
What is the maximum bend arc for steel gas piping 90 degrees
What is the purpose of an evaporator pressure regulator? Maintains a set minimum Pressure
What type of instrument is used to measure humidity Hygrometer
If an existing wall is rated at R-8 and new insulation is 0.4
added of R-15, what is the new U-Valve?
U-Value = 1/(sum of all R-Value)
What is the principle difference between a heat pump and Reversing Valve
a unit used for cooling only?
,Arizona HVAC Exam Review | C-39 Air Conditioning & Refrigeration Practice Questions, Answers & Licensing Prep 2026-2027
Which device prevents oil slugging? Crankcase Heater
What device is used to prevent slugging in a heat pump? Accumulators
When can a duct penetrate a fire wall? When protected with a listed fire damper
How often should the low water fuel shutoff shutoff should Daily
be tested using the blowdown method
What maximum temperature may a refrigerant cylinder be 120 *F
safely heated to in order to speed up the charging
process?
What limits the temperature of a burner? High Limit Control
The highest temperature at which a substance may be Critical Temperature
liquefied
What setting should the fuel gas valve be set for the Per Manufacturer
boiler?
What minimum size screen mesh should cover a 1/4 inch
combustion air inlet?
What happens when insulation gets wet? Reduces Heat - Insulation Qualities
Which of the following gases are not permitted for use in Oxygen
the testing of fuel gas systems?
What is the boiling point of R-134a at atmospheric -14.9 *F
pressure?
On Low Pressure Steam Systems and hot water boilers, Aluminum Shall NOT BE USED
which of the following material shall not be used?
Maximum spacing for hangers for horizontal steel pipe on 12 Feet
a hydronic system is?
All of the following are true of a chilled water system They are used primarily in residential systems
except
, Arizona HVAC Exam Review | C-39 Air Conditioning & Refrigeration Practice Questions, Answers & Licensing Prep 2026-2027
Repeated bending off soft copper tubing may cause it to Work Hardened
become
What is the maximum smoke developed rating of foam Smoke developed index of 450 or less
plastic insulation
In a hermetically sealed system, the oil in the crankcase is Winding Insulation Failure
tested and found to be acidic, what could be the cause or
source of this?
The minimum ID size for a fuel oil return line is 1/4 in. ID
Gas piping can be installed underground beneath a if installed in a conduit.
building:
The condensate line on a air conditioner can not drain by Drain Pump
gravity a ________ must be used to remove the
condensate to the outdoors
What does the potential relay do when energized? Disengaged the start capacitor
A furnace, located on a roof shall be installed on a 3 in 12
substantial level platform, when the roof has a slope of
_________ or greater, a level working platform, at least
30inches in an dimension shall be provided along the
firebox and control sides of the furnace
In a gas furnace, a yellow tipped flame indicates: Too little primary air
What is the minimum outside air required for a residential 2 .75 cfm/ sq ft
car garage
In a conventional wood frame construction, 2x6 nominal 1 3/8 inches
size wood studs in exterior walls and bearing partitions,
maybe be cut or notched to a maximum depth of
What types of controls are found on an HVAC system Electric, Pneumatic, Electronic
What is the minimum AFUE (Annual Fuel Utilization 78%
Efficiency) rating in a furnace?
How often must the relief valve on a low pressure boiler be Monthly
inspected?
How is the low water fuel shutoff tested? Blowdown Test
