# Free EPA 608 Type 3 Practice Test

The EPA 608 Type III section covers low-pressure appliances, mainly centrifugal chillers using refrigerants like R-123, R-11 and R-245fa. Because these systems run partly in a vacuum, leaks pull air in instead of pushing refrigerant out, and the test covers purge units, hot-water leak testing, recovery, recharging and the 25 mm Hg evacuation level. It's 25 questions plus 25 Core.

## Key takeaways

- Type III is for low-pressure chillers: refrigerants below 45 psia at 104 °F.
- Low-pressure systems leak air in, so excessive purging is the classic leak sign.
- Evacuate to 25 mm Hg absolute before a major repair, whatever the age of your recovery equipment.
- These are original practice questions, not real exam questions.

> **Independent practice questions**
>
> BRIX wrote these Type III questions from EPA's public Section 608 pages and the federal regulation. They are not real exam questions. BRIX is not affiliated with EPA, ESCO, Mainstream or any other certifying organization, and passing this practice test doesn't certify you. Only an EPA-approved certifying organization can.

## Who needs EPA 608 Type III certification?

Anyone who maintains, services, repairs or disposes of low-pressure appliances needs Type III or Universal certification ([40 CFR 82.161](https://www.ecfr.gov/current/title-40/chapter-I/subchapter-C/part-82/subpart-F/section-82.161)). That's mostly commercial chiller techs, building engineers in hospitals, campuses and office towers, and service techs for chiller manufacturers. A Type II card does not cover a low-pressure chiller.

A low-pressure appliance uses a refrigerant with a saturation pressure below 45 psia at 104 °F ([40 CFR 82.152](https://www.ecfr.gov/current/title-40/chapter-I/subchapter-C/part-82/subpart-F/section-82.152)). The regulation lists R-11, R-123, R-113 and R-245fa as examples. If you never expect to touch a centrifugal chiller, you can skip Type III and stop at Type II. If your shop takes commercial work, Universal is usually worth the extra 25 questions.

## Why low-pressure systems are their own section

In a high-pressure system, a leak lets refrigerant out. In a low-pressure chiller, parts of the system sit below atmospheric pressure, so a leak lets air and moisture in. Almost every Type III topic follows from that one fact:

- **Purge units** exist to pull out the air and noncondensables that leak in. A purge unit that runs constantly is the standard sign of a leak.
- **Leak testing** raises the system's pressure with heat first (hot water, or a built-in device such as Prevac), and only then nitrogen, according to EPA's topic list.
- **Water in the tubes can freeze** as pressure drops during evacuation or as liquid flashes during charging. That's why you circulate or drain the water and charge vapor before liquid.
- **The evacuation target is absolute pressure,** 25 mm Hg absolute, not inches of vacuum.

## What's on the Type III section?

**EPA 608 Type III topics and what to know**

| Topic | What you should be able to answer |
| --- | --- |
| Leak detection | Hot water or a built-in heating device first, then nitrogen; excessive purging as a sign of a leak; leak inspection and chronic-leaker reporting |
| Leak repair | Thresholds for chillers with 50+ lb of R-11 or R-123: 10% comfort cooling, 30% industrial process; the separate HFC rule for R-245fa-type systems |
| Recovery techniques | Liquid first, then vapor; heat oil to 130 °F before removing it; circulate or drain water to prevent freezing |
| Recharging | Vapor before liquid; charge centrifugals through the evaporator charging valve |
| Evacuation requirements | 25 mm Hg absolute; 0 psig for non-major repairs; the 85 °F boiling-point rule for how you may pressurize |
| Refrigeration and safety | Purpose of the purge unit; low-pressure PT relationships; ASHRAE 15 oxygen deprivation sensor plus a refrigerant sensor for R-123 |

_Topics from EPA's official Type III list (2026-10-24)._

## The evacuation and pressurization rules for chillers

Table 1 of [40 CFR 82.156](https://www.ecfr.gov/current/title-40/chapter-I/subchapter-C/part-82/subpart-F/section-82.156) sets one number for low-pressure appliances: 25 mm Hg absolute, for recovery equipment made before or after November 15, 1993 and at any charge size. That's simpler than Type II. The harder questions are about the opposite direction, raising pressure for a non-major repair.

**Opening a low-pressure appliance (our summary of 40 CFR 82.156(a))**

| Situation | What the rule requires |
| --- | --- |
| Major repair or disposal | Evacuate to 25 mm Hg absolute and verify the level before opening |
| Non-major repair, not vented afterward | Pressurize to no higher than 0 psig before opening; cover openings if you can't isolate |
| Refrigerant boils at or below 85 °F at atmospheric pressure | Don't use methods such as nitrogen that need purging afterward |
| Refrigerant boils above 85 °F at atmospheric pressure | Use heat to raise pressure as far as possible; nitrogen may make up the rest to atmospheric |
| Oil change | Evacuate or pressurize to no higher than 5 psig, or drain oil into a receiver brought to that limit |
| Leaks prevent reaching 25 mm Hg | Isolate; take leaking parts as low as you can without contaminating the refrigerant, never above 0 psig |

_Source: 40 CFR 82.156(a), verified 2026-10-24._

## How are Type III questions different from Type II?

Type II rewards memorizing numbers. Type III rewards understanding why a chiller behaves the way it does. Many questions give you a symptom or a step and ask for the reason. Here's one from our bank:

> **Sample Type III question**
>
> **When recharging a low-pressure chiller after evacuation, what goes in first?**
>
> A. Liquid, to save time · B. Vapor, so water in the tubes doesn't freeze · C. Nitrogen · D. Oil
>
> **Answer: B.** Liquid entering a deep vacuum flashes and gets very cold. Vapor first raises the pressure so the tube water stays liquid.

Leak repair also reads differently here. Whenever a chiller holds 50 or more pounds of an ozone-depleting refrigerant such as R-11 or R-123, the [82.157](https://www.ecfr.gov/current/title-40/chapter-I/subchapter-C/part-82/subpart-F/section-82.157) thresholds apply: 10% for comfort cooling, 30% for industrial process work. A chiller on R-245fa falls outside 82.157 but, since January 1, 2026, inside the AIM Act leak repair rule at [40 CFR 84.106](https://www.ecfr.gov/current/title-40/chapter-I/subchapter-C/part-84/subpart-C/section-84.106).

## How to study for Type III

1. **Start from "air leaks in."** For any question, ask what a vacuum-side leak would do. That explains purging, the leak test order and why nitrogen is a second choice.
2. **Memorize the four temperatures and pressures in this section:** 25 mm Hg absolute, 0 psig, 5 psig for oil changes, and 130 °F for oil heating. Add the 85 °F boiling-point line.
3. **Learn the order of operations:** liquid out first, then vapor; vapor in first, then liquid; heat first, then nitrogen.
4. **Know the R-123 safety extra.** ASHRAE 15 calls for a refrigerant sensor for R-123 on top of the oxygen deprivation sensor all equipment rooms need.
5. **Pair it with Type II.** Most techs who need Type III also need Type II, and both together with Type I make Universal. Try the [Universal practice test](https://www.brix.so/practice/epa-608/universal) once each section clears 70%.

### More EPA 608 practice

- [All EPA 608 practice tests](https://www.brix.so/practice/epa-608): Which section to take, plus a 20-question diagnostic
- [Core practice test](https://www.brix.so/practice/epa-608/core): 36 questions: ozone, the Clean Air Act, the three Rs, safety
- [Type I practice test](https://www.brix.so/practice/epa-608/type-1): 28 questions: small appliances and passive recovery
- [Type II practice test](https://www.brix.so/practice/epa-608/type-2): 33 questions: high-pressure systems, leak repair, evacuation levels
- [Universal practice test](https://www.brix.so/practice/epa-608/universal): All 125 questions; exam mode is 100 questions
- [EPA 608 certification guide](https://www.brix.so/certifications/epa-608): Who needs it, how to test, lost cards, A2L refrigerants

## Frequently asked questions

### What equipment does EPA 608 Type III cover?

Type III covers low-pressure appliances, defined as equipment using a refrigerant with a saturation pressure below 45 psia at 104 °F. In practice that means centrifugal chillers on refrigerants like R-11, R-123, R-113 and R-245fa.

### Can a Type II tech work on a low-pressure chiller?

No. The regulation requires Type III or Universal certification to maintain, service, repair or dispose of low-pressure appliances. Type II covers medium-, high- and very high-pressure equipment only.

### What vacuum level does Type III require before opening a chiller?

Before a major repair or disposal, a low-pressure appliance must be evacuated to 25 mm Hg absolute. The level is the same whether the recovery equipment was made before or after November 15, 1993.

### Why do low-pressure chillers have purge units?

Parts of a low-pressure chiller operate below atmospheric pressure, so leaks draw in air and moisture. The purge unit removes those noncondensables. A purge unit that runs far more than normal is a sign the chiller is leaking.

### Is Type III worth getting if I only do residential HVAC?

Strictly, no; residential systems are Type II equipment. But Universal certification requires Type III, so if you might work on chillers later, taking all three sections in one sitting gets you Universal without a second trip to a test site.

## Related

- [Free EPA 608 Practice Tests](https://www.brix.so/practice/epa-608)
- [Free EPA 608 Core Practice Test](https://www.brix.so/practice/epa-608/core)
- [Free EPA 608 Type 2 Practice Test](https://www.brix.so/practice/epa-608/type-2)
- [Free EPA 608 Universal Practice Test](https://www.brix.so/practice/epa-608/universal)
- [EPA 608 Certification: Who Needs It and How to Get It](https://www.brix.so/certifications/epa-608)
- [How to Start an HVAC Business in 2026 (Costs, Licenses and First Customers)](https://www.brix.so/start/hvac)
- [HVAC Software That Answers the Phone, Books the Tech and Keeps the Books](https://www.brix.so/for/hvac)
- [BTU Calculator](https://www.brix.so/tools/btu-calculator)
- [AC Tonnage Calculator](https://www.brix.so/tools/hvac-tonnage-calculator)
- [Superheat Calculator](https://www.brix.so/tools/superheat-calculator)

## Sources

- [EPA — Section 608 Technician Certification Test Topics](https://www.epa.gov/section608/section-608-technician-certification-test-topics) (checked 2026-10-24)
- [EPA — Section 608 Technician Certification Requirements](https://www.epa.gov/section608/section-608-technician-certification-requirements) (checked 2026-10-24)
- [eCFR — 40 CFR 82.152 Definitions](https://www.ecfr.gov/current/title-40/chapter-I/subchapter-C/part-82/subpart-F/section-82.152) (checked 2026-10-24)
- [eCFR — 40 CFR 82.156 Proper evacuation of refrigerant (Table 1)](https://www.ecfr.gov/current/title-40/chapter-I/subchapter-C/part-82/subpart-F/section-82.156) (checked 2026-10-24)
- [eCFR — 40 CFR 82.157 Appliance maintenance and leak repair](https://www.ecfr.gov/current/title-40/chapter-I/subchapter-C/part-82/subpart-F/section-82.157) (checked 2026-10-24)
- [eCFR — 40 CFR 84.106 Leak repair (AIM Act, HFCs)](https://www.ecfr.gov/current/title-40/chapter-I/subchapter-C/part-84/subpart-C/section-84.106) (checked 2026-10-24)
- [eCFR — 40 CFR 82.161 Technician certification](https://www.ecfr.gov/current/title-40/chapter-I/subchapter-C/part-82/subpart-F/section-82.161) (checked 2026-10-24)
- [eCFR — 40 CFR Part 82, Subpart F, Appendix D (test standards)](https://www.ecfr.gov/current/title-40/chapter-I/subchapter-C/part-82/subpart-F) (checked 2026-10-24)

Talk to BRIX: call or text (518) 588-1122, email eeharris2004@gmail.com, or book a 15-minute call at https://cal.com/ethanharris/15min.

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Written by BRIX Editorial Team. Last updated 2026-10-24.
Canonical: https://www.brix.so/practice/epa-608/type-3