EPA Section 608 — Type III
Leak detection: practice questions
Our EPA 608 Type III bank has 13 questions on this topic. Here are 5 of them with answers; the full mock exam draws from every topic, like the real one.
Question 1
What does a purge unit that runs often or for long periods indicate?
- Too much oil
- A perfectly tight system that is running at full capacity
- A leak that is letting air into the system
- A low water flow
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C. A leak that is letting air into the system — Frequent purging means air is entering; find and fix the leak.
Question 2
Which method can be used to raise the pressure of a low-pressure system for leak testing?
- Oxygen
- An open flame
- Controlled hot water or heating blankets, or dry nitrogen
- Compressed air
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C. Controlled hot water or heating blankets, or dry nitrogen — Never exceed 10 psig.
Question 3
Why do leaks in the low side of a low-pressure system let air and moisture in?
- Because the refrigerant is lighter than air
- Because the evaporator operates below atmospheric pressure
- Because the compressor pulls a vacuum on the condenser while it runs
- Because the purge unit pushes air in
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B. Because the evaporator operates below atmospheric pressure — Non-condensables then collect in the condenser.
Question 4
What gas can be used to leak test a low-pressure system without exceeding 10 psig?
- Acetylene
- Oxygen
- Compressed shop air, with a regulator
- Dry nitrogen, with a regulator
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D. Dry nitrogen, with a regulator — Never use oxygen or compressed air.
Question 5
Where are leaks most likely to be found on a low-pressure chiller?
- In the middle of the condenser shell
- At gaskets, fittings and valve packings, especially where the system is under vacuum
- On the control panel
- In the cooling tower fan
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B. At gaskets, fittings and valve packings, especially where the system is under vacuum — Seals degrade with age and thermal cycling.