Certification Exam RETAs Practice Test

Ammonia Refrigeration Operator Certification Exam (RETAs) Practice Test Questions And Correct Answers (Verified Answers) Plus Rationales 2026 Q&A | Instant Download Pdf

Q1.Which of the following is the primary function of a compressor in an ammonia refrigeration system?

• To condense the refrigerant vapor
• To increase the pressure and temperature of the refrigerant vapor
• To absorb heat from the evaporator
• To regulate refrigerant flow to the evaporator

Rationale: The compressor’s role is to compress low-pressure vapor to a

high-pressure, high-temperature state for condensation.

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Q2.What type of ammonia is commonly used in industrial refrigeration systems?

A. R-717

• Anhydrous ammonia
• Ammonium hydroxide
• Aqueous ammonia solution

Rationale: Anhydrous ammonia (R-717) is the pure, water-free form used

as a refrigerant in industrial systems.

Q3.Which of the following components is responsible for rejecting heat to the environment?

• Evaporator
• Condenser
• Receiver
• Compressor

Rationale: The condenser removes heat from the high-pressure refrigerant

vapor, condensing it into a liquid.

Q4. 2 / 4

Ammonia has a pungent odor that can be detected at concentrations as low

as:

• 5 ppm
• 10 ppm
• 20 ppm
• 50 ppm

Rationale: The odor threshold for ammonia is about 20 ppm, allowing

leaks to be detected early.

Q5.Which material is NOT compatible with ammonia refrigerant?

• Steel
• Copper
• Iron
• Stainless steel

Rationale: Copper reacts chemically with ammonia, forming compounds

that can damage the system.

Q6.

The receiver in an ammonia refrigeration system is used to:

• Evaporate the refrigerant
• Store liquid refrigerant 3 / 4

• Separate oil from ammonia
• Increase vapor pressure

Rationale: The receiver stores liquid refrigerant from the condenser for

distribution to the system.

Q7.What is the chemical formula for ammonia?

A. H₂O

B. NH₄OH

C. NH₃

D. N₂O

Rationale: Ammonia consists of one nitrogen atom bonded to three

hydrogen atoms — NH₃.

Q8.

When liquid ammonia is released into the atmosphere, it rapidly:

• Solidifies
• Vaporizes
• Dissolves in air
• Condenses

Rationale: Due to its low boiling point (-28°F), ammonia quickly vaporizes

when released.

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