9 Universal Certification Practice Exam Free Online FlashCards

How do CFCs contribute to stratospheric ozone depletion?

Ultraviolet radiation breaks down CFCs in the stratosphere, releasing chlorine atoms that contribute to ozone destruction.

How do recovery, recycling, and reclamation differ?

Recovery removes refrigerant; recycling reduces contaminants for reuse; reclamation processes and verifies refrigerant to a specified purity standard.

What is generally prohibited when servicing stationary refrigeration equipment?

Intentional release of refrigerant to the atmosphere is generally prohibited during service, repair, or disposal, subject to limited exceptions.

Why must a recovery cylinder stay within its fill limit?

Refrigerant expands as it warms; an overfilled cylinder lacks sufficient vapor space and can develop dangerous pressure.

Which gas is appropriate for pressure-testing a refrigeration system?

Use dry nitrogen with a regulator and appropriate pressure controls. Do not use oxygen or compressed air.

What refrigerant-charge limit defines a small appliance?

A small appliance is generally factory-manufactured, charged, and hermetically sealed with five pounds or less of refrigerant.

What recovery percentage is required when a small-appliance compressor functions?

For a small appliance with a functioning compressor, certified recovery equipment must recover at least 90% of the refrigerant.

What generally speeds the start of recovery from a system with liquid and vapor?

Recover available liquid refrigerant first; this generally removes more refrigerant per unit time than vapor-only recovery.

What pressure is required before opening a high-pressure appliance for a qualifying non-major repair?

For a non-major repair not followed by evacuation to the atmosphere, a high- or very-high-pressure appliance must be at 0 psig before opening.

Why should a hermetic compressor not run under deep vacuum?

Do not energize a hermetic compressor under deep vacuum; it can be damaged, including by electrical arcing in the low-pressure environment.

How should many zeotropic refrigerant blends be charged?

Many blended refrigerants should be charged as liquid to reduce fractionation and preserve the intended composition. Follow refrigerant and equipment instructions.

What can excessive purging from a low-pressure chiller indicate?

Excessive purging can indicate that air or other noncondensables are entering the system, potentially through a leak.