Nevada C-21B Air Conditioning Contractor
Practice Exam 2025/2026 Latest Questions &
Verified Answers | Instant PDF Download
1 - Which component of a vapor-compression refrigeration cycle
compresses refrigerant vapor and raises its pressure and
temperature?
Evaporator
Compressor
Condenser
Expansion device
Answer: Compressor
2 - Under EPA Section 608, what is required for technicians to legally
purchase and service regulated refrigerants?
A Nevada contractor license only
EPA Section 608 technician certification
A local building permit
Union membership card
Answer: EPA Section 608 technician certification
3 - Which joining method and filler material is commonly used to
connect copper refrigeration lines for high-pressure systems?
Soft solder (tin-lead) with rosin flux
Silver brazing (hard solder) with appropriate flux
Crimped mechanical compression fittings without brazing
Fluxless TIG welding
Answer: Silver brazing (hard solder) with appropriate flux
,4 - When recovering refrigerant from a system, which personal
protective equipment (PPE) should technicians typically wear? (Select
all that apply.)
Chemical-resistant gloves
Safety glasses or face shield
Respirator (when working in confined spaces or where vapor
exposure is possible)
Lightweight court shoes (no steel toe)
Answer: Chemical-resistant gloves, Safety glasses or face shield,
Respirator (when working in confined spaces or where vapor
exposure is possible)
5 - Which of the following are common causes of reduced cooling
capacity in an air conditioning system? (Select all that apply.)
Low refrigerant charge
Dirty or restricted evaporator coil
Failing compressor
Oversized supply ductwork
Answer: Low refrigerant charge, Dirty or restricted evaporator coil,
Failing compressor
6 - What is the primary function of a thermostatic expansion valve
(TXV) in a refrigeration circuit?
Maintain constant head pressure in the condenser
Regulate refrigerant flow to maintain proper superheat at the
evaporator outlet
Filter oils and contaminants from the refrigerant
Increase refrigerant pressure entering the condenser
Answer: Regulate refrigerant flow to maintain proper superheat at the
evaporator outlet
7 - Best practice for installing an outdoor condensing unit is to place it:
, In a shaded, level area on a firm pad with adequate clearance for
airflow and service access
Directly against the house siding to minimize refrigerant line
length
In a recessed pit below grade to protect from weather
On combustible material to prevent corrosion
Answer: In a shaded, level area on a firm pad with adequate
clearance for airflow and service access
8 - Which steps are part of a proper electrical lockout/tagout
procedure for HVAC service? (Select all that apply.)
Shut off power at the unit disconnect or circuit breaker
Apply locks and tags to the disconnect to prevent re-energizing
Verify the equipment is de-energized with a properly rated meter
Notify the equipment manufacturer before servicing
Answer: Shut off power at the unit disconnect or circuit breaker, Apply
locks and tags to the disconnect to prevent re-energizing, Verify the
equipment is de-energized with a properly rated meter
9 - What does the SEER rating indicate for an air conditioning
system?
Seasonal Energy Efficiency Ratio — the cooling output divided
by electrical energy input over a typical cooling season
Static Efficiency Emission Rating
Maximum instantaneous cooling capacity at peak load
Sound Emission Efficiency Rating
Answer: Seasonal Energy Efficiency Ratio — the cooling output
divided by electrical energy input over a typical cooling season
10 - Which system components are required to be electrically
grounded/bonded in HVAC installations? (Select all that apply.)
Metal equipment housings and control panels
Outdoor condensing unit casing and compressor mounting
Ductwork that is part of the equipment assembly
Practice Exam 2025/2026 Latest Questions &
Verified Answers | Instant PDF Download
1 - Which component of a vapor-compression refrigeration cycle
compresses refrigerant vapor and raises its pressure and
temperature?
Evaporator
Compressor
Condenser
Expansion device
Answer: Compressor
2 - Under EPA Section 608, what is required for technicians to legally
purchase and service regulated refrigerants?
A Nevada contractor license only
EPA Section 608 technician certification
A local building permit
Union membership card
Answer: EPA Section 608 technician certification
3 - Which joining method and filler material is commonly used to
connect copper refrigeration lines for high-pressure systems?
Soft solder (tin-lead) with rosin flux
Silver brazing (hard solder) with appropriate flux
Crimped mechanical compression fittings without brazing
Fluxless TIG welding
Answer: Silver brazing (hard solder) with appropriate flux
,4 - When recovering refrigerant from a system, which personal
protective equipment (PPE) should technicians typically wear? (Select
all that apply.)
Chemical-resistant gloves
Safety glasses or face shield
Respirator (when working in confined spaces or where vapor
exposure is possible)
Lightweight court shoes (no steel toe)
Answer: Chemical-resistant gloves, Safety glasses or face shield,
Respirator (when working in confined spaces or where vapor
exposure is possible)
5 - Which of the following are common causes of reduced cooling
capacity in an air conditioning system? (Select all that apply.)
Low refrigerant charge
Dirty or restricted evaporator coil
Failing compressor
Oversized supply ductwork
Answer: Low refrigerant charge, Dirty or restricted evaporator coil,
Failing compressor
6 - What is the primary function of a thermostatic expansion valve
(TXV) in a refrigeration circuit?
Maintain constant head pressure in the condenser
Regulate refrigerant flow to maintain proper superheat at the
evaporator outlet
Filter oils and contaminants from the refrigerant
Increase refrigerant pressure entering the condenser
Answer: Regulate refrigerant flow to maintain proper superheat at the
evaporator outlet
7 - Best practice for installing an outdoor condensing unit is to place it:
, In a shaded, level area on a firm pad with adequate clearance for
airflow and service access
Directly against the house siding to minimize refrigerant line
length
In a recessed pit below grade to protect from weather
On combustible material to prevent corrosion
Answer: In a shaded, level area on a firm pad with adequate
clearance for airflow and service access
8 - Which steps are part of a proper electrical lockout/tagout
procedure for HVAC service? (Select all that apply.)
Shut off power at the unit disconnect or circuit breaker
Apply locks and tags to the disconnect to prevent re-energizing
Verify the equipment is de-energized with a properly rated meter
Notify the equipment manufacturer before servicing
Answer: Shut off power at the unit disconnect or circuit breaker, Apply
locks and tags to the disconnect to prevent re-energizing, Verify the
equipment is de-energized with a properly rated meter
9 - What does the SEER rating indicate for an air conditioning
system?
Seasonal Energy Efficiency Ratio — the cooling output divided
by electrical energy input over a typical cooling season
Static Efficiency Emission Rating
Maximum instantaneous cooling capacity at peak load
Sound Emission Efficiency Rating
Answer: Seasonal Energy Efficiency Ratio — the cooling output
divided by electrical energy input over a typical cooling season
10 - Which system components are required to be electrically
grounded/bonded in HVAC installations? (Select all that apply.)
Metal equipment housings and control panels
Outdoor condensing unit casing and compressor mounting
Ductwork that is part of the equipment assembly
