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EPA 608 NEC 2023

EPA 608 Type 3 Exam Practice Test 4

Free EPA 608 Type III Exam Practice Test 4. 25 questions covering major repair definition (evaporator), vapor recovery preserving oil, large vacuum pump freeze risk, non-condensables causing high discharge pressure, hot water as best operating-system leak check, heating bottle for vapor charging, water circulation for refrigerant freeze prevention, high head pressure as leak indicator, moisture causing acid formation, large leak system depressurization, R-11 CFC properties and phase-out date, Type III scope for sub-atmospheric systems, centrifugal compressor impeller operation, high-efficiency purge unit, R-245fa as HFC replacement, oil selection for R-123, 25 mm Hg EPA recovery requirement, centrifugal surge and prevention, variable inlet guide vanes, leak rate obligations for owners, R-11 production ban, comfort cooling threshold for chilled water systems, rupture disk burst procedure, halide torch and electronic detector use, and ASHRAE Standard 15 monitoring.

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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: Under EPA, a major repair means maintenance or service of the evaporator in a low-pressure system. In Type III systems, liquid is removed first (it is faster), then the remaining vapor is recovered; vapor recovery removes very little oil. If non-condensables are present in an operating low-pressure system, expect high discharge (head) pressure. An operating low-pressure system can be leak-checked by applying hot water to raise system pressure briefly above atmospheric.

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EPA 608 Type 3 Exam Practice Test 4 — Question List

Question 1: As per EPA guidelines a major repair means, maintenance or service of which of the following component?

Evaporator
Filter drier
Expansion line

Question 2: Which of the following recovery method does not pull the oil from the system during evacuation?

Vapor recovery
Liquid recovery

Question 3: If a large vacuum pump is used during evacuation …………….

It may cause freezing of trapped water
The evacuation process will speed up
The refrigerant may get freeze in the evacuation hoses

Question 4: If non condensables present in the operating refrigeration system ………………………….

The refrigerant leak rate will increase
The discharge pressure increases
The moisture present in the system freezes
Spoils condenser coil

Question 5: Which of the following is the best leak checking method in operating low pressure refrigeration system?

Hot water
Pressurizing with Nitrogen gas
Pressurizing with oxygen
Hydro-static tube unit.

Question 6: Heating a refrigerant bottle will speed of ………………………….

Vapor charging
Liquid charging

Question 7: Water must be circulated through chillers during evacuating a system to avoid ……………

Refrigerant Freezing
Refrigerant leaking
Water tube damage

Question 8: In low pressure refrigeration system, which of the following is the good indicator of leak?

High head pressure
Moisture present in the system
Low pressure than atmosphere
compressor motor slowing down

Question 9: What happens to the system when moisture presents in an operating system?

Acid will form
Moisture will freeze
Prevents evacuation
Refrigerant leakage will happen

Question 10: If a system has a large leak enough to prevent evacuation must be brought to …………………. Before being opened.

Atmospheric pressure
10 psig
Below atmospheric pressure
Below 15 psig.

Question 11: R-11 (CFC-11) was banned from production in 1995. What classification of refrigerant is R-11, and what are its two most notable environmental values?

R-11 is an HFC with ODP=0 and GWP=100 — it is being phased down for climate reasons
R-11 is a CFC with ODP=1.0 (highest ozone depletion) and GWP=4,750 — production banned December 31, 1995
R-11 is an HCFC with ODP=0.055 — in the same family as R-22
R-11 is a natural refrigerant with zero ODP — it was banned due to toxicity concerns only

Question 12: What is the defining operating characteristic that makes a refrigerant a "low-pressure" Type III refrigerant?

Low-pressure refrigerants operate at exactly 14.7 PSIA — they match atmospheric pressure exactly
Low-pressure refrigerants have an evaporator pressure below atmospheric (sub-atmospheric vacuum) during normal chiller operation
Low-pressure refrigerants require lower ambient temperature to operate — only used in arctic climates
Low-pressure refers to the discharge pressure — these refrigerants have low condenser pressures

Question 13: In a centrifugal chiller, what happens to refrigerant vapor as it passes from the center (eye) to the outer edge of the spinning impeller?

The refrigerant cools as it moves outward — the centrifugal force causes temperature drop
Centrifugal force accelerates the vapor outward at high velocity; the surrounding diffuser then converts this velocity into higher pressure
The impeller traps pockets of refrigerant and mechanically squeezes them, directly increasing pressure
The refrigerant moves inward from the outer edge to the center, gaining pressure as it compresses

Question 14: A low-pressure chiller's purge unit has been running much more frequently than usual. What does this indicate, and what should a technician do?

High purge run time means the chiller is working harder than normal — increase the chilled water flow rate
High purge run time indicates air is entering through a system leak — locate and repair the leak
High purge run time is normal in hot summer weather — it increases automatically with outdoor temperature
High purge run time means the purge unit is malfunctioning — replace it immediately

Question 15: What makes R-245fa (HFC-245fa) the preferred long-term refrigerant for new low-pressure centrifugal chiller designs?

R-245fa is preferred because it operates at high pressure, making leak detection easier
R-245fa has zero ODP as an HFC — not subject to Montreal Protocol phase-out, providing long-term regulatory stability for new equipment investments
R-245fa is cheaper than R-123 to produce — it is the economical choice only
R-245fa has zero ODP and zero GWP — it has no environmental impact at all

Question 16: A technician is retrofitting an R-11 chiller to R-123. The existing system uses mineral oil. What must be done to the oil before charging with R-123?

Nothing needs checking; any oil works with any refrigerant
Follow the chiller manufacturer's retrofit instructions and use the oil they specify for R-123
Drain a small amount of mineral oil to make room for R-123 — partial oil change is sufficient
Add POE oil on top of the mineral oil — the mixture will be compatible with R-123

Question 17: A technician has recovered most of the refrigerant from an R-123 chiller by pushing it out under pressure. The system still has some vapor remaining. What must be done next before the system can be opened?

Open the system immediately — once the liquid is removed, vapor recovery is not required
Pull a final vacuum to 25 mm Hg absolute using recovery equipment and verify with a micron gauge before opening
Add nitrogen to atmospheric pressure first, then open the system without further vacuum
The system can be opened at any vacuum level — the 25 mm Hg requirement only applies to high-pressure systems

Question 18: What audible and physical signs indicate that a centrifugal chiller is surging, and why is this dangerous?

Surge produces no sound — it can only be detected by measuring discharge pressure
Surge produces a loud thump or bang with vibration — dangerous because flow reversal shocks bearings and impeller blades
Surge causes the chiller to make a high-pitched whine — it is not dangerous and clears on its own
Surge produces steam from the condenser — it means the condenser water temperature is too high

Question 19: What percentage of full load capacity can a centrifugal chiller typically reach before hot gas bypass must engage to prevent surge, when using variable inlet guide vanes (IGVs) alone?

5% of full load — IGVs can reduce capacity to near zero without any surge risk
Approximately 10–25% of full load — below this, refrigerant flow is too low for stable centrifugal compression and hot gas bypass must engage
50% of full load — centrifugal compressors can only operate at half capacity or above without surging
IGVs have no effect on surge — surge is prevented only by the hot gas bypass valve

Question 20: A building owner decides not to repair a leaking 2,000 lb R-11 chiller because the refrigerant is expensive and they plan to replace the chiller "someday." The system leaks 400 lbs per year. Is the owner in compliance with EPA Section 608?

Yes — there is no requirement to repair if the owner intends to replace the equipment eventually
No — a 20% leak rate exceeds the 10% comfort cooling threshold; repair (or a retrofit/retirement plan) is required within 30 days
Yes — R-11 systems are exempt from leak repair requirements since R-11 production was banned in 1995
No — but only if the chiller is in a state with its own stricter regulations

Question 21: Since R-11 production was banned in December 1995, where does the R-11 that is still used in existing chillers come from?

R-11 is still manufactured under special EPA permit for existing chiller use
Reclaimed R-11 — recovered from decommissioned equipment, purified to AHRI 700 standards, then resold for existing chiller maintenance
R-11 is imported from countries that do not follow the Montreal Protocol
No R-11 is available anywhere — all existing R-11 chillers must be immediately retired

Question 22: Why is a large centrifugal chiller used for building air conditioning subject to the 10% leak repair threshold rather than the 20% commercial refrigeration threshold?

Centrifugal chillers exceed 50 lbs, which triggers the stricter threshold for all large systems
The threshold is set by the application, not size — comfort cooling (building air conditioning) uses 10% regardless of chiller size
The stricter threshold applies only because R-11 is a CFC
Centrifugal chillers are always industrial process refrigeration at 30%

Question 23: A low-pressure chiller loses cooling water flow on a hot summer day. The evaporator gradually warms up. What will eventually happen if cooling water is not restored?

The chiller will automatically switch to air cooling mode if condenser water is lost
The refrigerant warms and pressure rises; at 15 PSIG the rupture disk bursts and releases refrigerant into the equipment room
Nothing happens — low-pressure systems are designed to operate indefinitely without cooling water
The compressor overheats and trips off; the refrigerant remains safely contained

Question 24: A technician uses a halide torch to check an R-11 system for leaks after slightly pressurizing with nitrogen to 5 PSIG. The flame turns green at the shaft seal area. What does this indicate?

The green flame means nitrogen from the pressurization is present — the halide torch detects nitrogen
Green flame indicates chlorine from R-11 — the nitrogen pressure reversed the normal sub-atmospheric flow, pushing R-11 vapor outward at the shaft seal
The green flame is a false positive — halide torches always turn green when nitrogen is used for pressurization
Green means no leak — the halide torch only changes color when moisture is present

Question 25: What must be posted OUTSIDE the entrance to a mechanical room containing R-123 centrifugal chillers, according to ASHRAE Standard 15 safety requirements?

Nothing is required to be posted outside — all safety information is kept inside the mechanical room
Refrigerant type(s), emergency contacts, emergency procedures, and equipment shutoff location must be posted outside the entrance
Only a "No Smoking" sign is required outside the mechanical room
The EPA certificate of the building owner must be displayed outside the mechanical room

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%

RegulationEPA Section 608

DifficultyIntermediate

Last reviewedJun 2026

Timer starts immediately. Progress is auto-saved.

Source: EPA Section 608 (40 CFR Part 82)