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EPA 608 NEC 2023

EPA 608 Type 2 Exam Practice Test 4

Free EPA 608 Type II Exam Practice Test 4. 25 questions on system dehydration, R-12 vapor pre-charge procedure, nitrogen for freeze prevention during evacuation, open vs hermetic compressors, commercial refrigeration leak thresholds, inert gas leak checking, vapor recovery and oil retention, pressure relief valve installation, accumulator position, liquid recovery limitations, nitrogen brazing purge, oil foaming causes, non-condensable removal, liquid slugging prevention, valve core replacement procedures, R-22 oil compatibility, moisture prevention during assembly, short-cycling diagnosis, refrigeration service valve types, R-22 to HFC retrofit, high-pressure cutout, scroll vs reciprocating compressor differences, recovery before component replacement, Section 608 certification requirements, and refrigerant type identification before service.

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The EPA 608 certification is required by law for any technician who purchases or handles refrigerants. It covers safe handling, leak detection, recovery, and environmental regulations.

Type I covers small appliances (≤5 lbs refrigerant), Type II covers high-pressure systems, Type III covers low-pressure systems, and Universal covers all three. Most HVAC technicians pursue Universal certification.

You must score at least 70% on each section of the exam. The Universal exam has four parts: core, Type I, Type II, and Type III.

Key facts for this test: Dehydration (removing water/moisture) is done by deep evacuation with a vacuum pump. For R-12 (CFC-12) water-cooled systems, charge vapor to 33 psig first to prevent moisture from freezing. Dry nitrogen is used to raise system pressure during evacuation breaks to prevent water from freezing solid inside the system. Open-type compressors have the motor outside the compressor body. Food storage refrigeration leak threshold = 35% per year (commercial category).

25

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45 min

Time

70%

Pass

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EPA 608 Type 2 Exam Practice Test 4 — Question List

Question 1: A refrigerant system is dehydrated to …………………..

Remove the oil and vapour
Remove the water and moisture
Remove the nitrogen trapped in system
Remove the refrigerant

Question 2: The best method to prevent the freezing of moisture in CFC-12 refrigerant system is to charge with vapor first until the pressure of ………….

33 psig
48 psig
74 psig
94 psig

Question 3: Which of the following gas is used to increase the pressure in the system to prevent freezing during evacuation?

Liquid nitrogen
Dry nitrogen
Liquid hydrogen
Dry hydrogen

Question 4: In the open type compressor the motor is located …………. the compressor body.

Outside
Inside
on

Question 5: A annual leak rate of ……………. % or more should be repaired in food storage refrigeration system which has more than 50 pounds or more charge.

15
34
35
18

Question 6: Which of the following is a perfect leak checking method for a built-up system before charging it?

Pressurizing the system with inert gas
Pressurizing the system with R-410
Removing the vacuum using a vacuum pump
Pressurizing the system with liquid refrigerant

Question 7: Which of the following refrigerant recovery technique minimizes the leakage of the oil in the system?

Recovering a system in a vapour phase
Recovering a system in a liquid phase
Purging the system with pressurised nitrogen before recovery
Recovering the system in faster mode.

Question 8: In which of the following combination the pressure relief valves should not installed?

Series
Parallel
Vertically
Horizontally

Question 9: Which of the following component directly following the evaporator in the refrigeration system?

Receiver
Metering device
Accumulator
Condenser

Question 10: What is the shortcoming of liquid recovery method in the refrigeration system?

Some liquid remains in the system
Some vapour remains in the system
Some oil remains in the system

Question 11: Why must a technician flow dry nitrogen through copper tubing while brazing refrigerant lines?

To test for leaks while the joint is being brazed
To prevent copper oxide scale from forming inside the tubing during the brazing process
To cool the copper tubing quickly so the joint sets faster
Nitrogen is not used during brazing — only after, for pressure testing

Question 12: What causes oil foaming in a compressor crankcase at startup?

The oil becomes contaminated with water during evacuation
Refrigerant dissolves into cold oil during the off-cycle and flashes out as foam when the compressor starts
The compressor oil is overfilled and creates foam when circulating
Non-condensable gases mix with oil in the crankcase and cause foaming

Question 13: How can a technician tell if a recovery cylinder contains non-condensable gases, and how should they be removed?

Shake the cylinder — non-condensables make a rattling sound
Compare cylinder pressure to the P-T chart value; if higher than expected, purge from the vapor port
Non-condensables are heavier and settle at the bottom — drain through the liquid port
Non-condensables cannot be removed from a recovery cylinder — the cylinder must be discarded

Question 14: What is liquid slugging in a refrigeration compressor, and what serious damage can it cause?

Liquid refrigerant coating the compressor exterior and causing corrosion
Liquid refrigerant entering the compressor suction, causing extreme pressure spikes that can bend rods and crack valves
Oil turning liquid-thin due to excessive heat, reducing lubrication
Liquid refrigerant bypassing the expansion device through the liquid line

Question 15: A Schrader valve core on a pressurized R-22 system is leaking. Can the valve core be replaced without recovering the refrigerant?

No — refrigerant must always be recovered before any valve work
Yes, only with a valve core removal tool that maintains seal during replacement; otherwise recover first
Yes — refrigerant pressure actually helps push the old core out and the new one in
Schrader valve cores can never be replaced — the entire service valve must be changed

Question 16: A technician is adding refrigerant to a running R-22 air conditioning system that appears to be slightly undercharged. Which charging method should be used to determine the correct final charge amount?

Add refrigerant until the suction pressure equals 70 psig for R-22, then stop
Use the subcooling method — add refrigerant until condenser outlet subcooling matches manufacturer specification
Add refrigerant until the sight glass is completely clear with no bubbles, then add 2 more lbs
The charging method does not matter — just add refrigerant until the system cools properly

Question 17: What type of lubricating oil is used in R-22 refrigeration systems?

POE (polyolester) oil — required for all modern refrigerants
Mineral oil or alkylbenzene (AB) oil — both compatible with R-22 HCFC systems
Synthetic automotive motor oil — provides best protection at high temperatures
No oil is used in R-22 systems — the refrigerant self-lubricates

Question 18: After brazing new refrigerant lines, what steps should be taken to minimize moisture contamination before the system is charged?

No precautions needed — the filter-dryer will handle any moisture automatically
Cap all open tubing ends, evacuate deeply before charging, and install a new filter-dryer
Blow compressed air through the lines before sealing to remove moisture
Moisture only enters through the refrigerant cylinder — no field precautions are needed

Question 19: What is "short-cycling" in a refrigeration or A/C system, and what problems does it cause?

Short-cycling means the compressor runs continuously without shutting off
Short-cycling is when the compressor turns on and off very frequently, causing excessive wear and overheating
Short-cycling means the refrigerant circuit has a short in the liquid line
Short-cycling is normal for residential systems and causes no harm

Question 20: What is the difference between a ball valve and a service (stem) valve in a commercial refrigeration system?

Ball valves and service valves are identical — they just have different names
Ball valve = two positions (open/closed), no service port; service valve = three positions with a gauge service port
A ball valve allows gauge connection; a service valve does not
Ball valves are for liquid lines only; service valves are for vapor only

Question 21: What must be done to an existing R-22 system before it can be retrofitted to R-407C or another HFC refrigerant?

Nothing — just recover the R-22 and charge with the new HFC refrigerant
Flush and replace the mineral oil with POE oil; install a new filter-dryer; evacuate before recharging
Only the filter-dryer needs to be changed — the old mineral oil is compatible with HFCs
R-22 systems cannot be retrofitted to HFC refrigerants under any circumstances

Question 22: What triggers a low-pressure cutout (LPCO) to shut off the compressor, and how is this different from a high-pressure cutout?

LPCO shuts off the compressor when discharge pressure is too low
LPCO shuts off the compressor when suction pressure drops below a set minimum, protecting against low charge and motor overheating
LPCO opens a bypass valve to add refrigerant automatically when pressure drops
LPCO and HPCO monitor the same pressure — they are the same device

Question 23: Before replacing ANY refrigerant-containing component (compressor, TXV, filter-dryer, etc.) on a commercial R-22 system, what is the first step?

Power off the equipment — recovery is not required before standard maintenance
Recover all refrigerant (or isolate and recover the section) to the required level before opening the circuit
Only recover refrigerant if the charge is over 50 lbs — small systems can be opened directly
Vent the refrigerant outdoors in a well-ventilated area before opening the system

Question 24: Under EPA Section 608, who is required to be certified as a refrigerant technician?

Only large commercial businesses with more than 10 employees
Any person who, for compensation, maintains, services, repairs, or disposes of appliances containing regulated refrigerants
Only technicians who work on systems with more than 50 lbs of refrigerant
Certification is voluntary — there is no legal requirement to be certified

Question 25: Why does vapor-phase recovery minimize oil loss from the refrigeration system compared to liquid-phase recovery?

Vapor recovery uses a smaller cylinder, so less oil is needed to fill the dead space
Oil does not evaporate with refrigerant vapor — vapor recovery leaves oil in the system
Vapor recovery operates at higher pressure, which separates oil from refrigerant
Vapor and liquid recovery have identical oil loss — the method makes no difference

Study Tip: The EPA 608 exam is closed book. Memorize: recovery is required before opening any refrigerant system. Venting refrigerant is illegal. Know the ODP and GWP values for R-22, R-410A, R-134a, R-32, and R-454B.

EXAM CARD EPA 608

Questions25

Time limit45 min

Pass score70%

Code editionNEC 2023

DifficultyIntermediate

Last reviewedJun 2026

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Source: EPA Section 608 (40 CFR Part 82)