What is the EPA Type 3 Certification?

The EPA Type 3 certification covers low-pressure appliances. These are systems that operate in a vacuum (below atmospheric pressure). The most common example is a large industrial centrifugal chiller.

Technicians with type 3 epa certification are highly sought after in commercial and industrial sectors. But first, you must pass the exam.

Industrial Centrifugal Chiller

Large industrial chillers are the primary focus of Type 3.

Interactive Type 3 Questions

Test your knowledge on low-pressure systems.

Question 1
What is the rupture disc burst pressure on a low-pressure chiller?
A. 10 psig
B. 15 psig
C. 25 psig
Click to see answer in App
Question 2
Where does the purge unit remove air from?
A. Top of condenser
B. Bottom of evaporator
C. Compressor oil sump
Click to see answer in App

Key Topic 1: Leak Rate Regulations

Just like Type 2, the epa practice test type 3 requires you to know leak rates. Since most chillers are large industrial units, they often fall into the higher brackets.

Appliance Type Leak Rate %
Industrial Process 30%
Commercial Refrigeration 20%
Comfort Cooling (Office Chillers) 10%

Key Topic 2: Recovery Levels (The 25 mm Hg Rule)

Low-pressure recovery is unique because we measure in absolute pressure (mm Hg absolute), not inches of vacuum. This is the #1 question on the exam.

  • Standard Recovery: You must recover refrigerant to 25 mm Hg absolute.
  • Why? This ensures almost all refrigerant is removed before opening the system.
  • High-Efficiency Purge: Purge units also help remove non-condensables (air) that leak into the system.

Key Topic 3: Purge Units & Safety

Because Type 3 systems operate in a vacuum, air leaks in (instead of refrigerant leaking out). The Purge Unit is essential.

  • Function: Removes air and non-condensables from the top of the condenser (where air accumulates).
  • Safety: The rupture disc is a safety device on the evaporator that bursts at 15 psig to prevent over-pressurization.
  • Charging: Always introduce refrigerant vapor first until pressure rises above freezing (32°F) to prevent freezing water tubes.

Type 3 FAQs

What is "epa type 3"?

It is the EPA 608 certification for maintaining and repairing low-pressure appliances, such as centrifugal chillers.

Do I need Type 3 for residential AC?

No. Residential AC is Type 2. Type 3 is strictly for low-pressure units found in large commercial buildings.

What is 25 mm Hg absolute?

It is the required evacuation level for low-pressure appliance recovery. It equals approximately 29 inches Hg vacuum.

How do I warm the oil?

You should turn on the oil heaters (crankcase heaters) to 130°F before removing oil to reduce the amount of refrigerant in the oil.

Explore Other Sections

Core Regulations & Safety
Type I Small Appliances
Type II High Pressure / AC
P-T Chart Reference Tool

Ready to Pass Type 3?

Master purge units, rupture discs, and recovery procedures with our epa type 3 practice test.

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