EPA Section 608 — Type II
Leak detection: practice questions
Our EPA 608 Type II bank has 10 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 should limit the pressure used for a nitrogen leak test?
- The appliance's design (nameplate) pressure, with a regulator and relief valve in use
- The highest pressure the nitrogen cylinder can deliver, so that small leaks are found fast
- The outdoor temperature only
- 500 psig on every system
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A. The appliance's design (nameplate) pressure, with a regulator and relief valve in use — Nitrogen cylinders can exceed 2,000 psig.
Question 2
Excessive superheat in a system with a fixed metering device often indicates:
- An overcharge
- A low refrigerant charge
- Too much airflow at the condenser only
- A clean filter
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B. A low refrigerant charge — Low charge starves the evaporator, raising superheat.
Question 3
Which leak location is very common in air-conditioning systems?
- The thermostat display
- Mechanical joints such as flare fittings and service valve cores
- The air filter
- The middle of straight runs of copper tubing, away from any joints or fittings
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B. Mechanical joints such as flare fittings and service valve cores — Vibration and thermal cycling loosen fittings over time.
Question 4
What is a standing pressure test?
- Measuring voltage while standing
- Adding refrigerant until frost forms
- Pressurizing the system with dry nitrogen and watching for a pressure drop over time
- Running the compressor at full load
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C. Pressurizing the system with dry nitrogen and watching for a pressure drop over time — Never exceed the system's design pressure.
Question 5
Before leak testing a system that contains refrigerant, what should you do?
- Pressurize with compressed air
- Add oxygen to find leaks
- Vent the refrigerant
- Recover the refrigerant, then pressurize with nitrogen (a trace of R-22 may be used as a tracer)
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D. Recover the refrigerant, then pressurize with nitrogen (a trace of R-22 may be used as a tracer) — Refrigerant may not be used as the pressurizing gas.