WISCONSIN HVAC DSPS QUALIFIER EXAM 2026-2027
VERIFIED ANSWERS PLUS RATIONALES | GRADED
Q&A STUDY GUIDE
1. Which Wisconsin State agency is primarily responsible for the administration and
enforcement of commercial building, plumbing, and HVAC trade credential licensing and
codes?
A. Department of Natural Resources (DNR)
B. Department of Safety and Professional Services (DSPS)
C. Department of Commerce and Economic Development
D. Department of Workforce Development (DWD)
The Department of Safety and Professional Services (DSPS) is the governing Wisconsin state
body responsible for overseeing professional credentialing, including HVAC qualifiers, master
plumbers, and commercial building code enforcement under Wisconsin Administrative Code.
2. According to Wisconsin SPS 323, what is the maximum allowable warm air supply
temperature for a gravity-type warm air furnace installed in a residential dwelling?
A. 120 degrees Fahrenheit
B. 160 degrees Fahrenheit
C. 200 degrees Fahrenheit
D. 250 degrees Fahrenheit
Under Wisconsin Administrative Code SPS 323 (Heating, Ventilating and Air Conditioning),
gravity warm air supply systems are restricted to a maximum discharge temperature of 250
degrees Fahrenheit to prevent structural thermal degradation and fire hazards.
3. When installing combustion air piping for a Category IV direct-vent furnace in a tightly
constructed Wisconsin home, what is the minimum required clearance to an interior
corner from the sidewall termination?
A. 6 inches
B. 12 inches
C. 24 inches
D. 36 inches
Standard mechanical code and manufacturer specifications adopted under Wisconsin SPS
323/364 mandate a minimum clearance of 12 inches from sidewall vent terminations to inside
corners to prevent re-circulation of flue gases and localized moisture accumulation.
,4. A technician is calculating the outdoor air ventilation requirement for an office space
measuring 2,000 square feet with an expected occupancy of 10 people under ASHRAE 62.1
standards. What is the baseline minimum ventilation rate requirement?
A. Combined CFM derived from per-person and per-square-foot rates
B. Flat rate of 15 CFM per occupant only
C. 0.35 air changes per hour exclusively
D. 50 CFM per 100 square feet regardless of occupancy
ASHRAE 62.1 (and SPS 364 adoption) utilizes the Ventilation Rate Procedure, which calculates
total outdoor air requirements by summing the area component (CFM/sq ft) and the occupant
component (CFM/person).
5. What is the primary operational effect of an overcharged capillary tube residential air
conditioning system?
A. Decreased subcooling and increased superheat
B. Increased subcooling and increased suction pressure
C. High superheat and low head pressure
D. Zero subcooling and compressor vacuum
In a fixed-orifice or capillary tube system, excess refrigerant backs up into the condenser,
which increases liquid subcooling and forces higher operating pressures across both suction
and discharge sides.
6. An HVAC contractor in Wisconsin alters the ductwork of an existing commercial
building. Under SPS 364, when are approved plans required to be submitted for
examination?
A. For every residential and commercial modification regardless of size
B. Only when the modification involves spaces exceeding 50,000 cubic feet
C. When the system expansion or alteration affects heat loss/gain by more than 50,000
BTU/hr
D. Plans are never required for alterations, only for new construction
Wisconsin Administrative Code SPS 364 requires plan submission and approval for HVAC
building modifications or additions when the total heating or cooling capacity alteration
exceeds 50,000 BTU/hr or involves critical life safety mechanical ventilation alterations.
7. Which formula accurately describes Ohm's Law for calculating total resistance in a
single-phase electrical circuit?
A. Resistance = Voltage x Current
B. Resistance = Voltage / Current
C. Resistance = Current / Voltage
,D. Resistance = Watts x Voltage
Ohm's Law states that Resistance (R) equals Voltage (E) divided by Current (I), expressed as R
= E / I.
8. What is the minimum required slope for horizontal pitch on a Category I appliance gas
vent according to NFPA 54 / National Fuel Gas Code?
A. 1/16 inch per foot upward toward the termination
B. 1/8 inch per foot downward toward the termination
C. 1/4 inch per foot upward toward the termination
D. 1/2 inch per foot downward toward the appliance
Category I gas vents must maintain a continuous upward slope of not less than 1/4 inch per
foot from the appliance collar to the vent termination to ensure proper natural thermal
buoyancy of combustion products.
9. When testing a 24V HVAC transformer secondary winding with a multimeter set to
measure resistance, an "OL" reading across the disconnected secondary leads indicates
what condition?
A. An internal short circuit
B. Normal secondary winding resistance
C. An open electrical winding
D. Ground fault leakage
An "OL" (over limit/open line) resistance reading indicates infinite electrical resistance,
meaning the copper wire in the secondary transformer winding is physically severed or
burned open.
10. In a commercial VAV system, what device regulates the volume of conditioned air
delivered to a specific thermal zone?
A. Face and bypass damper
B. Thermostatic expansion valve
C. Modulating zone terminal unit damper
D. Constant volume return fan
VAV (Variable Air Volume) terminal units utilize modulating zone dampers controlled by
space thermostats to adjust airflow volume into the zone based on actual thermal demand.
11. What type of motor relies on a run capacitor connected permanently in series with its
auxiliary winding to increase operational efficiency?
A. Shaded pole motor
, B. Permanent Split Capacitor (PSC) motor
C. Split-phase motor
D. Capacitor-Start Induction-Run (CSIR) motor
PSC motors use a run capacitor continuously energizing the start/auxiliary winding during
operation, providing higher running efficiency and smoother torque compared to split-phase
designs.
12. Under EPA Section 608 regulations, what is the maximum allowable annual leak rate
for comfort cooling systems containing 50 or more pounds of Class I or Class II ozone-
depleting refrigerant?
A. 10 percent
B. 15 percent
C. 20 percent
D. 30 percent
Effective January 1, 2019, EPA Section 608 regulations established a 10% annual leak rate
threshold for comfort cooling appliances containing 50+ lbs of ozone-depleting or substitute
refrigerants before mandatory repair is triggered.
13. A residential hydronic boiler system uses a compression tank. What is the primary
purpose of this component?
A. To heat domestic hot water indirectly
B. To absorb volumetric water expansion as system temperature rises
C. To purge air automatically during initial water filling
D. To regulate gas valve manifold pressure
Water expands as it is heated; because liquid water is non-compressible, a closed hydronic
system requires an expansion or compression tank to absorb this fluid volume increase and
prevent relief valve discharge.
14. What safety device must be installed on all closed-loop residential hydronic heating
boilers to prevent catastrophic over-pressurization?
A. Thermal cutoff switch
B. Pressure relief valve set to 30 PSI standard
C. Flow switch
D. Low water cutoff rated for 150 PSI
Residential low-pressure hydronic heating boilers are required by ASME and Wisconsin
mechanical codes to feature a pressure relief valve calibrated to discharge at 30 PSI.
VERIFIED ANSWERS PLUS RATIONALES | GRADED
Q&A STUDY GUIDE
1. Which Wisconsin State agency is primarily responsible for the administration and
enforcement of commercial building, plumbing, and HVAC trade credential licensing and
codes?
A. Department of Natural Resources (DNR)
B. Department of Safety and Professional Services (DSPS)
C. Department of Commerce and Economic Development
D. Department of Workforce Development (DWD)
The Department of Safety and Professional Services (DSPS) is the governing Wisconsin state
body responsible for overseeing professional credentialing, including HVAC qualifiers, master
plumbers, and commercial building code enforcement under Wisconsin Administrative Code.
2. According to Wisconsin SPS 323, what is the maximum allowable warm air supply
temperature for a gravity-type warm air furnace installed in a residential dwelling?
A. 120 degrees Fahrenheit
B. 160 degrees Fahrenheit
C. 200 degrees Fahrenheit
D. 250 degrees Fahrenheit
Under Wisconsin Administrative Code SPS 323 (Heating, Ventilating and Air Conditioning),
gravity warm air supply systems are restricted to a maximum discharge temperature of 250
degrees Fahrenheit to prevent structural thermal degradation and fire hazards.
3. When installing combustion air piping for a Category IV direct-vent furnace in a tightly
constructed Wisconsin home, what is the minimum required clearance to an interior
corner from the sidewall termination?
A. 6 inches
B. 12 inches
C. 24 inches
D. 36 inches
Standard mechanical code and manufacturer specifications adopted under Wisconsin SPS
323/364 mandate a minimum clearance of 12 inches from sidewall vent terminations to inside
corners to prevent re-circulation of flue gases and localized moisture accumulation.
,4. A technician is calculating the outdoor air ventilation requirement for an office space
measuring 2,000 square feet with an expected occupancy of 10 people under ASHRAE 62.1
standards. What is the baseline minimum ventilation rate requirement?
A. Combined CFM derived from per-person and per-square-foot rates
B. Flat rate of 15 CFM per occupant only
C. 0.35 air changes per hour exclusively
D. 50 CFM per 100 square feet regardless of occupancy
ASHRAE 62.1 (and SPS 364 adoption) utilizes the Ventilation Rate Procedure, which calculates
total outdoor air requirements by summing the area component (CFM/sq ft) and the occupant
component (CFM/person).
5. What is the primary operational effect of an overcharged capillary tube residential air
conditioning system?
A. Decreased subcooling and increased superheat
B. Increased subcooling and increased suction pressure
C. High superheat and low head pressure
D. Zero subcooling and compressor vacuum
In a fixed-orifice or capillary tube system, excess refrigerant backs up into the condenser,
which increases liquid subcooling and forces higher operating pressures across both suction
and discharge sides.
6. An HVAC contractor in Wisconsin alters the ductwork of an existing commercial
building. Under SPS 364, when are approved plans required to be submitted for
examination?
A. For every residential and commercial modification regardless of size
B. Only when the modification involves spaces exceeding 50,000 cubic feet
C. When the system expansion or alteration affects heat loss/gain by more than 50,000
BTU/hr
D. Plans are never required for alterations, only for new construction
Wisconsin Administrative Code SPS 364 requires plan submission and approval for HVAC
building modifications or additions when the total heating or cooling capacity alteration
exceeds 50,000 BTU/hr or involves critical life safety mechanical ventilation alterations.
7. Which formula accurately describes Ohm's Law for calculating total resistance in a
single-phase electrical circuit?
A. Resistance = Voltage x Current
B. Resistance = Voltage / Current
C. Resistance = Current / Voltage
,D. Resistance = Watts x Voltage
Ohm's Law states that Resistance (R) equals Voltage (E) divided by Current (I), expressed as R
= E / I.
8. What is the minimum required slope for horizontal pitch on a Category I appliance gas
vent according to NFPA 54 / National Fuel Gas Code?
A. 1/16 inch per foot upward toward the termination
B. 1/8 inch per foot downward toward the termination
C. 1/4 inch per foot upward toward the termination
D. 1/2 inch per foot downward toward the appliance
Category I gas vents must maintain a continuous upward slope of not less than 1/4 inch per
foot from the appliance collar to the vent termination to ensure proper natural thermal
buoyancy of combustion products.
9. When testing a 24V HVAC transformer secondary winding with a multimeter set to
measure resistance, an "OL" reading across the disconnected secondary leads indicates
what condition?
A. An internal short circuit
B. Normal secondary winding resistance
C. An open electrical winding
D. Ground fault leakage
An "OL" (over limit/open line) resistance reading indicates infinite electrical resistance,
meaning the copper wire in the secondary transformer winding is physically severed or
burned open.
10. In a commercial VAV system, what device regulates the volume of conditioned air
delivered to a specific thermal zone?
A. Face and bypass damper
B. Thermostatic expansion valve
C. Modulating zone terminal unit damper
D. Constant volume return fan
VAV (Variable Air Volume) terminal units utilize modulating zone dampers controlled by
space thermostats to adjust airflow volume into the zone based on actual thermal demand.
11. What type of motor relies on a run capacitor connected permanently in series with its
auxiliary winding to increase operational efficiency?
A. Shaded pole motor
, B. Permanent Split Capacitor (PSC) motor
C. Split-phase motor
D. Capacitor-Start Induction-Run (CSIR) motor
PSC motors use a run capacitor continuously energizing the start/auxiliary winding during
operation, providing higher running efficiency and smoother torque compared to split-phase
designs.
12. Under EPA Section 608 regulations, what is the maximum allowable annual leak rate
for comfort cooling systems containing 50 or more pounds of Class I or Class II ozone-
depleting refrigerant?
A. 10 percent
B. 15 percent
C. 20 percent
D. 30 percent
Effective January 1, 2019, EPA Section 608 regulations established a 10% annual leak rate
threshold for comfort cooling appliances containing 50+ lbs of ozone-depleting or substitute
refrigerants before mandatory repair is triggered.
13. A residential hydronic boiler system uses a compression tank. What is the primary
purpose of this component?
A. To heat domestic hot water indirectly
B. To absorb volumetric water expansion as system temperature rises
C. To purge air automatically during initial water filling
D. To regulate gas valve manifold pressure
Water expands as it is heated; because liquid water is non-compressible, a closed hydronic
system requires an expansion or compression tank to absorb this fluid volume increase and
prevent relief valve discharge.
14. What safety device must be installed on all closed-loop residential hydronic heating
boilers to prevent catastrophic over-pressurization?
A. Thermal cutoff switch
B. Pressure relief valve set to 30 PSI standard
C. Flow switch
D. Low water cutoff rated for 150 PSI
Residential low-pressure hydronic heating boilers are required by ASME and Wisconsin
mechanical codes to feature a pressure relief valve calibrated to discharge at 30 PSI.
