Nevada C-21B Refrigeration and Air Conditioning
Contractor Exam
Nevada C-21B Refrigeration and Air Conditioning
Contractor Exam
Nevada C-21B Refrigeration and Air Conditioning
Contractor Exam
Most Tested Exam Coverage Areas:
1. Refrigerant handling and EPA Section 608 recovery requirements
2. Condensate drainage, slope, and overflow protection under UMC
3. Refrigeration cycle components and thermodynamic principles
4. Load calculations and duct sizing fundamentals
5. Low-voltage controls, thermostats, and electrical safety
6. Piping materials, brazing, and pressure testing procedures
, 7. Nevada contractor licensing scope, bonds, and NSCB regulations
8. Safety regulations including OSHA fall protection and jobsite hazards
9. Equipment installation clearances and combustion air requirements
10. Troubleshooting system performance using superheat and subcooling
1. A Nevada C-21B contractor is preparing to open a residential split-system air
conditioner to replace a failed compressor, and the unit contains R-410A refrigerant;
what is the legally required action before any refrigerant line is disconnected?
A. Vent the remaining charge slowly because R-410A has zero ozone depletion
potential
B. Recover the refrigerant using EPA-certified equipment regardless of the system
charge size
C. Release the charge into a water bucket to dissolve the refrigerant safely
D. Only recover if the system contains more than 50 pounds of refrigerant
,Answer: B
EPA Section 608 prohibits intentional venting of ozone-depleting substances and their
substitutes, including R-410A, and requires recovery with certified equipment before
opening the system regardless of charge size . 8
2. While inspecting a horizontal condensate drain line from a rooftop cooling coil in
Las Vegas, the contractor observes the pipe running perfectly level for twelve feet
before terminating at a floor drain; what UMC requirement does this installation
violate?
A. The drain must slope not less than 1/8 inch per foot toward the discharge point
B. The drain must be sloped at exactly 1/4 inch per foot in all directions
C. The drain must be installed with a minimum diameter of two inches
D. The drain must include a cleanout every five feet of horizontal run
Answer: A
UMC 2018 Section 310.1 requires condensate waste piping to slope not less than 1/8
, inch per foot (approximately 1 percent) to prevent standing water and biological growth
. 6 10
3. A contractor is called to a commercial building where the primary condensate drain
from an air handler has clogged repeatedly, and overflow would damage ceiling tiles
and electrical fixtures below; which of the following is an acceptable overflow
protection method under UMC?
A. Installing a larger primary drain pipe only with no secondary protection
B. Plugging the overflow opening so the pan retains more water before spilling
C. Installing an auxiliary watertight pan with a separate drain or a water-level device
that shuts off the equipment
D. Routing the drain to the roof scupper so overflow goes outside
Answer: C
UMC 2018 Section 310.2 permits a secondary drain, an auxiliary pan with its own
drain, or a listed water-level detection device that de-energizes the equipment when
the primary drain clogs . 6
Contractor Exam
Nevada C-21B Refrigeration and Air Conditioning
Contractor Exam
Nevada C-21B Refrigeration and Air Conditioning
Contractor Exam
Most Tested Exam Coverage Areas:
1. Refrigerant handling and EPA Section 608 recovery requirements
2. Condensate drainage, slope, and overflow protection under UMC
3. Refrigeration cycle components and thermodynamic principles
4. Load calculations and duct sizing fundamentals
5. Low-voltage controls, thermostats, and electrical safety
6. Piping materials, brazing, and pressure testing procedures
, 7. Nevada contractor licensing scope, bonds, and NSCB regulations
8. Safety regulations including OSHA fall protection and jobsite hazards
9. Equipment installation clearances and combustion air requirements
10. Troubleshooting system performance using superheat and subcooling
1. A Nevada C-21B contractor is preparing to open a residential split-system air
conditioner to replace a failed compressor, and the unit contains R-410A refrigerant;
what is the legally required action before any refrigerant line is disconnected?
A. Vent the remaining charge slowly because R-410A has zero ozone depletion
potential
B. Recover the refrigerant using EPA-certified equipment regardless of the system
charge size
C. Release the charge into a water bucket to dissolve the refrigerant safely
D. Only recover if the system contains more than 50 pounds of refrigerant
,Answer: B
EPA Section 608 prohibits intentional venting of ozone-depleting substances and their
substitutes, including R-410A, and requires recovery with certified equipment before
opening the system regardless of charge size . 8
2. While inspecting a horizontal condensate drain line from a rooftop cooling coil in
Las Vegas, the contractor observes the pipe running perfectly level for twelve feet
before terminating at a floor drain; what UMC requirement does this installation
violate?
A. The drain must slope not less than 1/8 inch per foot toward the discharge point
B. The drain must be sloped at exactly 1/4 inch per foot in all directions
C. The drain must be installed with a minimum diameter of two inches
D. The drain must include a cleanout every five feet of horizontal run
Answer: A
UMC 2018 Section 310.1 requires condensate waste piping to slope not less than 1/8
, inch per foot (approximately 1 percent) to prevent standing water and biological growth
. 6 10
3. A contractor is called to a commercial building where the primary condensate drain
from an air handler has clogged repeatedly, and overflow would damage ceiling tiles
and electrical fixtures below; which of the following is an acceptable overflow
protection method under UMC?
A. Installing a larger primary drain pipe only with no secondary protection
B. Plugging the overflow opening so the pan retains more water before spilling
C. Installing an auxiliary watertight pan with a separate drain or a water-level device
that shuts off the equipment
D. Routing the drain to the roof scupper so overflow goes outside
Answer: C
UMC 2018 Section 310.2 permits a secondary drain, an auxiliary pan with its own
drain, or a listed water-level detection device that de-energizes the equipment when
the primary drain clogs . 6
