EPA 609 Leak Detection & System Diagnosis

Question 1

Which tool is specifically designed to detect refrigerant leaks in an MVAC system?

Accepted Answer

Electronic leak detector

Answer

Manifold gauge set

Answer

Vacuum pump

Answer

Refrigerant identifier

Question 2

What does a manifold gauge reading of 0 psi on BOTH the high and low sides most likely indicate?

Accepted Answer

The system has lost all refrigerant charge

Answer

The system is properly charged

Answer

The compressor is functioning normally

Answer

The expansion valve is stuck open

Question 3

UV dye is injected into an MVAC system primarily to:

Accepted Answer

Identify refrigerant leaks under ultraviolet light

Answer

Lubricate the compressor seals

Answer

Improve system cooling efficiency

Answer

Neutralize moisture contamination

Question 4

An MVAC system that blows warm air while the compressor is running could indicate:

Accepted Answer

A refrigerant leak causing low charge

Answer

Excessive refrigerant charge

Answer

A faulty blower motor resistor

Answer

Incorrect blend door calibration

Question 5

Frost or ice forming on the orifice tube or expansion valve in an MVAC system usually signals:

Accepted Answer

A restriction or moisture contamination causing a pressure/temperature drop

Answer

Normal refrigerant flow at high ambient temperatures

Answer

Overcharge of refrigerant

Answer

A faulty condenser fan motor

Question 6

When using an electronic leak detector, the probe should be moved:

Accepted Answer

Slowly along the bottom of hoses and fittings since refrigerant vapors are heavier than air

Answer

Quickly across large areas to cover more ground

Answer

Only around the compressor shaft seal

Answer

Above all system components since refrigerant vapors rise

Question 7

Before performing a leak check on an MVAC system, the technician should first:

Accepted Answer

Run the A/C for several minutes to pressurize all components

Answer

Evacuate the system completely

Answer

Add refrigerant until the system is fully charged

Answer

Disable the compressor clutch relay