NEVADA NV C-21B
AIR CONDITIONING
CONTRACTOR EXAM
QUESTIONS AND
VERIFIED ANSWERS
WITH RATIONALES
EXAM SPECIFICATIONS
Time Allocation: 4 Hours
Total Questions: 100 Questions
Question Format: Multiple Choice
Minimum Competency: 70% Required to Pass
Core Focus: HVAC Installation, Refrigeration, Code, Safety, Business
Nevada C-21B Air Conditioning Contractor Exam Page 1
, Exam Overview & Content Outline
EXAM PURPOSE
Nevada C-21B Air Conditioning Contractor Exam validates competency for HVAC contractors per
Nevada State Contractors Board. Covers refrigeration, air conditioning, heating systems, ductwork,
controls, code compliance, and business law.
CONTENT DISTRIBUTION
• Refrigeration & AC Systems (30%) — Refrigeration cycle, refrigerants, components, charging,
troubleshooting
• Heating & Ventilation (25%) — Gas furnaces, heat pumps, ductwork, airflow, ventilation codes
• Electrical & Controls (25%) — NEC Article 440, motors, controls, thermostats, safety devices
• Codes, Safety & Business (20%) — IMC, UMC, SMACNA, EPA 608, OSHA, NV contractor law
QUESTION FORMAT & SCORING
Each item presents four options. Correct answers are highlighted in green with checkmark (✓).
Every question includes detailed rationale with code references. Requires 70% to pass.
STUDY STRATEGY
Master refrigeration cycle: compressor, condenser, metering device, evaporator. Know refrigerant
types and EPA 608 rules. Understand NEC Article 440 for HVAC equipment. Study IMC/UMC for
installation codes. Know SMACNA duct standards. Review superheat/subcooling calculations. Study
NV contractor law NRS 624.
CURRICULUM ALIGNMENT
Questions reflect current standards: International Mechanical Code (IMC), Uniform Mechanical Code
(UMC), NEC Article 440, EPA Section 608, SMACNA, ACCA Manuals, and Nevada Revised Statutes
Chapter 624.
Nevada C-21B Air Conditioning Contractor Exam Page 2
, SECTION I: Refrigeration & AC Systems
1. Refrigeration cycle components in order:
A. Evaporator, Compressor, Condenser, Metering Device
✓ B. Compressor, Condenser, Metering Device, Evaporator
C. Condenser, Evaporator, Compressor, Metering Device
D. Metering Device, Evaporator, Compressor, Condenser
Rationale: Refrigeration cycle: Compressor (low pressure vapor to high pressure vapor), Condenser (rejects
heat, vapor to liquid), Metering Device/TXV (high pressure liquid to low pressure liquid), Evaporator (absorbs
heat, liquid to vapor). C-C-M-E. NV C-21B exam requires cycle knowledge for troubleshooting.
2. Superheat is measured at:
A. Condenser outlet
✓ B. Evaporator outlet/suction line
C. Liquid line
D. Discharge line
Rationale: Superheat: Temperature of vapor above saturation temperature. Measured at evaporator outlet
or compressor suction. Superheat = Actual temp - Saturation temp. Target: 8-12°F for TXV systems. Low
superheat = flooding (liquid to compressor). High superheat = starved evaporator. NV contractors must
charge by superheat.
3. Subcooling is measured at:
A. Suction line
✓ B. Condenser outlet/liquid line
C. Evaporator inlet
D. Compressor inlet
Rationale: Subcooling: Temperature of liquid below saturation temperature. Measured at condenser
outlet/liquid line. Subcooling = Saturation temp - Actual temp. Target: 10-15°F. Low subcooling =
undercharge or low airflow. High subcooling = overcharge or restriction. NV C-21B requires charging by
subcooling for TXV systems.
4. EPA Section 608 requires certification for:
A. Installing ductwork
✓ B. Handling refrigerants
C. Electrical work only
D. Painting units
Rationale: EPA 608: Required for anyone servicing, maintaining, repairing, or disposing of equipment
containing refrigerants. Types: Type I (small appliances), Type II (high-pressure), Type III (low-pressure),
Universal (all). Prohibits venting CFCs, HCFCs, HFCs. Leak repair required. NV contractors must have EPA
608 certification.
5. R-410A operates at what pressure vs R-22:
Nevada C-21B Air Conditioning Contractor Exam Page 3
AIR CONDITIONING
CONTRACTOR EXAM
QUESTIONS AND
VERIFIED ANSWERS
WITH RATIONALES
EXAM SPECIFICATIONS
Time Allocation: 4 Hours
Total Questions: 100 Questions
Question Format: Multiple Choice
Minimum Competency: 70% Required to Pass
Core Focus: HVAC Installation, Refrigeration, Code, Safety, Business
Nevada C-21B Air Conditioning Contractor Exam Page 1
, Exam Overview & Content Outline
EXAM PURPOSE
Nevada C-21B Air Conditioning Contractor Exam validates competency for HVAC contractors per
Nevada State Contractors Board. Covers refrigeration, air conditioning, heating systems, ductwork,
controls, code compliance, and business law.
CONTENT DISTRIBUTION
• Refrigeration & AC Systems (30%) — Refrigeration cycle, refrigerants, components, charging,
troubleshooting
• Heating & Ventilation (25%) — Gas furnaces, heat pumps, ductwork, airflow, ventilation codes
• Electrical & Controls (25%) — NEC Article 440, motors, controls, thermostats, safety devices
• Codes, Safety & Business (20%) — IMC, UMC, SMACNA, EPA 608, OSHA, NV contractor law
QUESTION FORMAT & SCORING
Each item presents four options. Correct answers are highlighted in green with checkmark (✓).
Every question includes detailed rationale with code references. Requires 70% to pass.
STUDY STRATEGY
Master refrigeration cycle: compressor, condenser, metering device, evaporator. Know refrigerant
types and EPA 608 rules. Understand NEC Article 440 for HVAC equipment. Study IMC/UMC for
installation codes. Know SMACNA duct standards. Review superheat/subcooling calculations. Study
NV contractor law NRS 624.
CURRICULUM ALIGNMENT
Questions reflect current standards: International Mechanical Code (IMC), Uniform Mechanical Code
(UMC), NEC Article 440, EPA Section 608, SMACNA, ACCA Manuals, and Nevada Revised Statutes
Chapter 624.
Nevada C-21B Air Conditioning Contractor Exam Page 2
, SECTION I: Refrigeration & AC Systems
1. Refrigeration cycle components in order:
A. Evaporator, Compressor, Condenser, Metering Device
✓ B. Compressor, Condenser, Metering Device, Evaporator
C. Condenser, Evaporator, Compressor, Metering Device
D. Metering Device, Evaporator, Compressor, Condenser
Rationale: Refrigeration cycle: Compressor (low pressure vapor to high pressure vapor), Condenser (rejects
heat, vapor to liquid), Metering Device/TXV (high pressure liquid to low pressure liquid), Evaporator (absorbs
heat, liquid to vapor). C-C-M-E. NV C-21B exam requires cycle knowledge for troubleshooting.
2. Superheat is measured at:
A. Condenser outlet
✓ B. Evaporator outlet/suction line
C. Liquid line
D. Discharge line
Rationale: Superheat: Temperature of vapor above saturation temperature. Measured at evaporator outlet
or compressor suction. Superheat = Actual temp - Saturation temp. Target: 8-12°F for TXV systems. Low
superheat = flooding (liquid to compressor). High superheat = starved evaporator. NV contractors must
charge by superheat.
3. Subcooling is measured at:
A. Suction line
✓ B. Condenser outlet/liquid line
C. Evaporator inlet
D. Compressor inlet
Rationale: Subcooling: Temperature of liquid below saturation temperature. Measured at condenser
outlet/liquid line. Subcooling = Saturation temp - Actual temp. Target: 10-15°F. Low subcooling =
undercharge or low airflow. High subcooling = overcharge or restriction. NV C-21B requires charging by
subcooling for TXV systems.
4. EPA Section 608 requires certification for:
A. Installing ductwork
✓ B. Handling refrigerants
C. Electrical work only
D. Painting units
Rationale: EPA 608: Required for anyone servicing, maintaining, repairing, or disposing of equipment
containing refrigerants. Types: Type I (small appliances), Type II (high-pressure), Type III (low-pressure),
Universal (all). Prohibits venting CFCs, HCFCs, HFCs. Leak repair required. NV contractors must have EPA
608 certification.
5. R-410A operates at what pressure vs R-22:
Nevada C-21B Air Conditioning Contractor Exam Page 3
