CRST Practice Test

The Certified Refrigeration Service Technician (CRST) credential from the Refrigerating Engineers & Technicians Association is designed for technicians with an active CARO or CIRO credential, or 4+ years of industrial refrigeration experience. This page provides free practice question sets, step-by-step worked solutions, and verified details on exam format, test centers, passing standards, and credential maintenance to help candidates prepare effectively.

CRST Exam at a Glance

What changed for CRST in 2026

• Oct 25, 2026: Eligibility changed to Active CARO or CIRO, or 4+ years of industrial refrigeration experience (previously Active CARO or CIRO credential, or 4+ years of industrial refrigeration experience).^[1]
• Oct 25, 2026: Testing window changed to Dates and times vary by location (previously Year-round; dates vary by test center).^[3]

What the CRST is and how it works

According to Refrigerating Engineers & Technicians Association, “An active CARO or CIRO credential or verification of at least four years of progressively responsible experience in industrial refrigeration is required.”^[1]

The Certified Refrigeration Service Technician (CRST) examination is administered by the Refrigerating Engineers & Technicians Association to verify service capabilities in industrial refrigeration. Candidates qualify by holding an active CARO or CIRO credential, or by verifying 4+ years of industrial refrigeration experience.

Testing is conducted at RETA Network and Kryterion test centers, with sessions scheduled directly by RETA staff. Available dates and times vary by location, so candidates must consult official RETA scheduling for local availability. The test consists of 150 multiple-choice questions, and candidates receive about 3 hours to complete the examination. The passing score is 70%.

For 2026, the examination fee is $770 for a RETA member and $1,060 for a non-member. If a candidate does not pass, a retest fee applies after the first unsuccessful attempt: $515 for members and $710 for non-members. To qualify for this retest discount, the first failed attempt must have occurred within the past year.

An earned credential has a validity of 3 years. Renewal is required every 3 years through documentation of 24 PDH (2.4 CEU).

Worked examples: how to reason through CRST questions

These are practice questions written for this site, not questions from the real exam. Each explanation shows why the right answer is right and why the others are wrong.

Example 1

Question: During a preventive maintenance visit on a walk-in cooler, the technician measures a high condensing temperature. Which maintenance item is MOST likely the root cause?

1. Worn compressor valve plates
2. Dirty or blocked condenser coil
3. Low refrigerant charge
4. Defective evaporator fan motor

Answer: B. Dirty or blocked condenser coil

Explanation:

Option B is correct because dirt or debris blocking the condenser coil restricts ambient airflow across the heat exchanger. This reduction in heat rejection raises condensing temperature and system head pressure. Option A is incorrect because worn compressor valve plates reduce pumping efficiency, leading to higher suction pressure and lower condensing pressure rather than high condensing temperature. Option C is incorrect because an undercharged system lacks sufficient vapor density, resulting in low operating pressures. Option D is incorrect because a failing evaporator fan reduces heat absorption at the cooling coil, which lowers suction pressure and reduces condenser thermal loading. As a general maintenance rule, high condensing temperature points directly to impaired heat rejection at the condenser.

Example 2

Question: What refrigerant recovery requirement applies to small appliances (systems containing 5 pounds or less of refrigerant)?

1. Full evacuation to 4 inches Hg vacuum before opening
2. Recovery of at least 80% of the refrigerant using certified equipment
3. No recovery required if the refrigerant is an HFC
4. Recovery using self-contained recovery equipment to EPA standards

Answer: D. Recovery using self-contained recovery equipment to EPA standards

Explanation:

Option D is correct because federal environmental regulations require technicians servicing small appliances to recover refrigerant using certified, self-contained recovery equipment that satisfies regulatory standards before opening the circuit. Option A is incorrect because pulling a vacuum to 4 inches Hg applies to larger commercial systems rather than the mandatory baseline for small appliance servicing. Option B is incorrect because recovering 80% represents an operating-compressor efficiency threshold under specific testing procedures rather than the broad recovery equipment mandate. Option C is incorrect because recovery rules apply strictly to hydrofluorocarbons, prohibiting intentional venting. The general rule for small appliances holding 5 pounds or less of refrigerant is that recovery equipment must be certified and self-contained to satisfy environmental protection requirements.

Example 3

Question: When pressure-testing a refrigeration system with nitrogen, what is the maximum test pressure typically used for medium-temperature applications?

1. 50 psig
2. 150 psig
3. 500 psig
4. 1,000 psig

Answer: B. 150 psig

Explanation:

Option B is correct because 150 psig represents the standard test pressure for medium-temperature refrigeration circuits, corresponding to low-side component design pressure ratings. This pressure level exposes potential joint and fitting leaks without overpressurizing system vessels. Option A is incorrect because 50 psig provides inadequate force to uncover small pinhole leaks or joint weaknesses during a nitrogen leak check. Option C is incorrect because 500 psig far exceeds low-side design thresholds and risks bursting evaporators, accumulators, or control diaphragms. Option D is incorrect because 1,000 psig creates an extreme rupture hazard well beyond the mechanical limits of commercial refrigeration equipment. The general rule when leak testing with nitrogen is to never exceed the low-side design working pressure indicated on the equipment nameplate.

How to use these practice tests

Begin preparation by auditing technical foundations across core topics using targeted practice sets. Review equipment principles with CRST Refrigeration Systems & Components and cycle physics with CRST Refrigerants & Thermodynamics. Include CRST Blueprint Reading & Technical Drawing and CRST Materials & Specifications to build familiarity with piping schematics and component ratings.

Next, focus on practical mechanical and electrical service tasks. Work through sets on CRST Electrical Systems & Controls, CRST Piping, Tubing & Brazing Techniques, and CRST Troubleshooting & Repair Techniques. For each missed question, consult manufacturer documentation and official RETA materials rather than memorizing answers.

Reinforce regulatory compliance and field practices with CRST Safety Procedures & Environmental Reg... and CRST Installation & Maintenance Practices.

Prior to test day, practice pacing across 150 multiple-choice questions within about 3 hours, striving for consistent scoring above the 70% passing threshold.

Sources & last verified

1. Refrigerating Engineers & Technicians Association — number of questions, time limit, passing score, exam fee (official source). “Format: Multiple-choice Number of questions: 150” Verified Oct 25, 2026.
2. Refrigerating Engineers & Technicians Association — validity, renewal (official source). “certification is valid for three years from test passage date or date of last three-year renewal cycle.” Verified Oct 25, 2026.
3. Refrigerating Engineers & Technicians Association — delivery, testing window (official source). “RETA CARO, CIRO, CRST, CRES and RAI tests are administered through RETA Network Test Centers and Kryterion Test Centers.” Verified Oct 25, 2026.

How we verify: editorial & fact-checking policy. Report an error: contact us.