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EPA 608 NEC 2023

EPA 608 Type 3 Exam Practice Test 3

Free EPA 608 Type III Exam Practice Test 3. 25 questions covering 350-ton R-11 chiller vapor quantity, large vacuum pump freeze prevention with nitrogen, idle low-pressure system pressure maintenance, liquid charging temperature conditions, purge unit purpose, heater placement for faster vapor evacuation, leak locations at gaskets and fittings, rupture disk failure at 10 PSIG, water-cooled condenser water source, low-pressure system refrigerant direction, Type III certification for sub-atmospheric systems, R-123 environmental benefits, surge and hot gas bypass, electronic and halide torch leak detection, rupture disk bursting emergency procedure, Section 608 requirements, compatible recovery cylinders, low-pressure recovery procedures, oil heater degas procedure, cooling tower function, EPA recovery level for Type III, centrifugal compressor operation, ASHRAE Standard 15 monitoring requirements, and lubricating oil for R-123.

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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: A 350-ton R-11 chiller contains approximately 100 lbs of vapor after liquid refrigerant is removed. When a large vacuum pump is causing trapped water to freeze, raise the system pressure by introducing nitrogen gas. An idle low-pressure system must maintain pressure slightly above atmospheric to prevent air from entering. Switch from vapor to liquid charging when the refrigerant saturation temperature reaches 36°F (above the freezing point of water).

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70%

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EPA 608 Type 3 Exam Practice Test 3 — Question List

Question 1: How much of vapor contains in a 350 ton R-11 chillier after all the liquid has been removed?

100 lbs
150 lbs
50 lbs
200 lbs

Question 2: By using a large vacuum pumps can cause trapped water freezing, what a technician can do to prevent this?

He should increase the system pressure by introducing nitrogen gas.
He should decrease the system pressure by introducing nitrogen gas
He should remove the liquid refrigerant before vapor liquid
He should remove the vapor refrigerant before liquid refrigerant.

Question 3: What should be done for low pressure refrigeration system when the system is idle?

The refrigerant should be recovered and kept the system idle.
The pressure in the system should increase to higher than atmosphere to prevent air accumulation in system
The oil must be removed from refrigeration system periodically
Nitrogen gas must be purged in to the system to prevent moisture freezing

Question 4: Under which of the following condition it is better start charging using liquid refrigerant?

When refrigerant saturation temperature reaches 360 F
When the refrigerant saturation temperature reaches 56 0F
When the temperature of water is above 360F
When the temperature of water reaches 560F

Question 5: The purpose of purge unit in the low pressure refrigeration system :

Removes the refrigerant from the system
Removes the air from the system
Removes the oil from the system

Question 6: Which of the following device will help in evacuating vapor fast from the refrigeration system?

A heater placed on recovery vessel side
A high vacuum pump can be used for recovery
A nitrogen gas can be purged in to system

Question 7: In which part of low pressure refrigeration system the leaks may occur?

Expansion valve
Gaskets & Fittings
Condenser tube
Evaporator fittings

Question 8: What damage causes to the low pressure refrigeration system if the pressure increases more than 10 psig?

Rupture disk fails
Gaskets & Fittings may fail
Shaft seals may fail
Large leak may occur in the system

Question 9: For heat removal in water cooled condensing system, where does the water come from?

Condenser recycling unit
Evaporator auxiliary unit
Deep wells
Municipal water supply

Question 10: In low pressure system whether the refrigerant can go out of the system?

Yes
No

Question 11: Which EPA 608 certification type covers technicians who service R-11 and R-123 centrifugal chillers?

Type II certification — large systems require the same certification as R-22 equipment
Type III certification — covers low-pressure sub-atmospheric refrigerant systems (R-11, R-123, R-245fa)
Type I certification — centrifugal chillers are hermetically sealed appliances
No certification is required — building owners are exempt from Section 608

Question 12: Compared to R-11, what are the key environmental advantages of using R-123 in centrifugal chillers?

R-123 is better because it operates at higher pressure — easier to detect leaks before they become large
R-123 has 98% lower ODP (0.02 vs 1.0) and 98% lower GWP (77 vs 4,750) compared to R-11
R-123 has zero ODP and zero GWP — it has absolutely no environmental impact
R-123 is environmentally identical to R-11 but is a synthetic replacement with lower cost

Question 13: When a centrifugal chiller is at very low load and risks going into surge, what does the hot gas bypass system do to prevent compressor damage?

Hot gas bypass increases the chilled water setpoint so the compressor does not have to work as hard
Hot gas bypass opens a valve that routes discharge gas back to the evaporator, creating artificial load to prevent surge
Hot gas bypass reduces compressor speed by temporarily reducing the motor voltage
Hot gas bypass injects oil into the compressor bearings to cushion the shock of surge

Question 14: A technician is checking an R-123 centrifugal chiller for leaks using a halide torch. The flame does not change color even though the system is losing refrigerant. What is the most likely reason?

The halide torch is faulty — a new torch should always detect R-123 leaks immediately
Low-pressure systems operate below atmospheric — refrigerant does not escape outward at leaks, so the torch cannot detect the leak location this way
R-123 does not contain chlorine, so the halide torch cannot detect it at all
The halide torch should be placed inside the chiller — external scanning never works

Question 15: A rupture disk on an R-123 chiller bursts during a hot summer day when the chiller lost cooling water. What is the FIRST action to take?

Immediately cover the ruptured disk with a rag to stop refrigerant from escaping
Evacuate all personnel from the equipment room immediately — refrigerant displacement creates asphyxiation risk
Start the chiller to re-pressurize the system and stop the release
Call the refrigerant supplier first to arrange emergency recharging

Question 16: A hospital owns a large R-123 chiller. Who is legally responsible for EPA Section 608 compliance — the hospital or the HVAC service contractor?

Only the HVAC contractor — the building owner is exempt since they do not touch the refrigerant
Both the building owner/operator and the service contractor are responsible and can be penalized for violations
Only the building owner — contractors are agents of the owner and cannot be penalized separately
Neither — hospitals have a medical exemption from EPA Section 608

Question 17: Can a recovery cylinder that previously contained R-11 be used to recover R-123 from a low-pressure chiller?

Yes — all low-pressure refrigerant recovery cylinders can be used interchangeably
No — cylinders must be dedicated to one refrigerant type; mixing refrigerants creates contamination that cannot be reclaimed
Yes — as long as the cylinder is emptied and flushed with nitrogen before use
Only if both refrigerants are HCFCs — R-11 and R-123 can be mixed safely

Question 18: When recovering refrigerant from a large R-11 chiller, a technician applies 12 PSIG to the evaporator to speed up recovery. Is this acceptable?

Yes — higher pressure means faster recovery, and 12 PSIG is still below the rupture disk rating
No — 12 PSIG exceeds the 10 PSIG maximum, risking rupture disk failure (rated at 15 PSIG)
Yes — the 10 PSIG limit only applies to older equipment made before 1993
No — any pressure applied to the evaporator is prohibited; only vacuum pumps may be used

Question 19: What is the purpose of the crankcase/oil heater that runs continuously on a centrifugal chiller during shutdown periods?

The oil heater keeps the compressor warm so it starts more easily in cold weather
The oil heater prevents refrigerant from dissolving into cold oil during shutdown — protecting against oil foaming and bearing damage on startup
The oil heater is only needed in very cold climates where the mechanical room may drop below freezing
The oil heater maintains oil at exact operating temperature so the chiller can restart instantly at any time

Question 20: What is the role of a cooling tower in a water-cooled centrifugal chiller system?

The cooling tower chills the chilled water going to the building air handlers
The cooling tower rejects heat from the condenser water to the atmosphere through evaporation, providing cool water to the condenser
The cooling tower stores spare refrigerant for emergency use when the chiller loses charge
The cooling tower pre-cools the refrigerant before it enters the evaporator

Question 21: Before opening a low-pressure centrifugal chiller for service, what final vacuum level must be achieved after recovery?

0 psig — just bring the system to atmospheric pressure before opening
25 mm Hg absolute (approximately 29 in. Hg vacuum) — the EPA required recovery level for low-pressure systems
15 in. Hg vacuum — the same requirement as for large high-pressure systems over 200 lbs
No vacuum is needed — simply recovering the liquid refrigerant is sufficient

Question 22: What component in a centrifugal compressor actually compresses the refrigerant vapor?

The piston compresses refrigerant by moving up and down in a cylinder
The impeller — a high-speed rotating disk with curved blades that uses centrifugal force to accelerate refrigerant vapor outward
The scroll compresses refrigerant by trapping it between two spiral plates
The solenoid valve compresses refrigerant by rapidly opening and closing against the vapor flow

Question 23: Where must the refrigerant detector be located in a chiller room containing R-123 equipment, according to ASHRAE Standard 15?

At ceiling height — refrigerant vapor rises and collects at the highest point
Near the floor — R-123 vapor is heavier than air and settles downward, requiring floor-level detection for early warning
Next to the chiller itself — placement at the equipment ensures the fastest detection
Outside the equipment room — internal detectors would be damaged by refrigerant exposure

Question 24: Why is alkylbenzene (AB) oil used in centrifugal chillers operating with R-123, rather than mineral oil?

AB oil costs less than mineral oil — it is the economical choice for large chiller systems
AB oil remains miscible with R-123 at cold evaporator temperatures; mineral oil separates and coats evaporator tubes, reducing heat transfer
AB oil has a lower viscosity — it flows faster through the compressor at high speeds
Mineral oil is perfectly acceptable for R-123 — AB oil is only needed for HFC refrigerants

Question 25: R-11 has an ODP of 1.0. What does this ODP value mean, and why is it significant?

ODP = 1.0 means R-11 has no ozone depletion potential — the scale goes from 0 to 100
ODP = 1.0 means R-11 is the reference standard for ozone destruction — one of the most damaging refrigerants to the ozone layer
ODP = 1.0 is a low value — it means R-11 is 1% as damaging as the worst refrigerants
ODP = 1.0 only applied during the 1980s — modern measurements show R-11 ODP is much lower

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)