EPA 609 Leak Detection & System Diagnosis 3

Question 1

Which type of leak detector offers the highest sensitivity for finding very small refrigerant leaks?

Accepted Answer

Heated diode (infrared) or heated element electronic detector

Answer

Heated diode and infrared electronic detectors are highly sensitive to refrigerant molecules and can detect leaks as small as 0.1 oz/year, far below what other methods can detect.

Question 2

A vacuum pull-down test is used in MVAC service to:

Accepted Answer

Verify the system holds a vacuum, confirming no leaks remain after repair

Answer

After evacuation, monitoring the vacuum gauge for 15–30 minutes confirms the system is leak-free and moisture-free — if vacuum rises (pressure increases), a leak or residual moisture is still present.

Question 3

Under EPA Section 609, if a technician discovers a leak during MVAC service, the required action is:

Accepted Answer

Recover the refrigerant and repair the leak before recharging

Answer

EPA 609 regulations require that leaks be repaired before refrigerant is recharged, preventing the intentional venting of refrigerant into the atmosphere.

Question 4

What does a restriction in the HIGH side of an MVAC system (such as a plugged liquid line drier) typically cause?

Accepted Answer

High pressure upstream of the restriction, low pressure downstream toward the metering device

Answer

A high-side restriction creates abnormally high pressure before the blockage and starves the metering device of liquid refrigerant downstream, reducing cooling performance.

Question 5

Nitrogen is sometimes used during leak testing of MVAC systems because:

Accepted Answer

Nitrogen is an inert, dry gas that safely pressurizes the system for leak checking without adding moisture

Answer

Dry nitrogen is inert and moisture-free, making it safe for pressurizing recovered or empty MVAC systems to locate leaks without risk of contamination or chemical reaction.

EPA 609 - EPA Section 609 Refrigerant Certification Practice Test

EPA 609 - EPA Section 609 Refrigerant Certification Practice Test

EPA 609 Leak Detection & System Diagnosis 3