EPA 608 Technician Certification: High-Pressure Leak Detection and Leak Repair Concepts
Importance ★★★★★ · 35% (estimate)
Overview
This chapter covers finding and fixing leaks in high-pressure equipment and the leak repair rules for large appliances. It explains common signs of leaks, which gas to use for a leak test, the trigger leak rates, repair and testing deadlines, inspections, and records.
Oil traces around joints and fittings and excessive superheat are common signs of a leak. Always leak test before charging. Nitrogen alone is the best test gas; nitrogen with a trace of R-22 is next, and both are better than pure refrigerant.
Under 40 CFR 82.157, appliances with 50 pounds or more of CFC or HCFC refrigerant must be repaired when the yearly leak rate is over 20 percent for commercial refrigeration, 30 percent for industrial process refrigeration, or 10 percent for comfort cooling and others. Since January 1, 2026, 40 CFR Part 84 applies the same rates to many appliances with 15 pounds or more of high-GWP HFC refrigerant.
Leaks must be repaired within 30 days, or 120 days if an industrial process shutdown is needed, and confirmed by an initial and a follow-up verification test. An owner who will not repair must make a retrofit or retirement plan within 30 days and finish it within a year. The leak rate is calculated each time refrigerant is added, and records are kept at least 3 years.
Key concepts
Trigger leak rates
For appliances with 50 lb or more of ODS refrigerant: 20% commercial refrigeration, 30% industrial process refrigeration, 10% comfort cooling and other appliances, per 12 months.
Memory tipCommercial 20, industrial 30, comfort 10.
Source: 40 CFR 82.157(c) (EPA Section 608 rules) · as of 2026
Repair deadline
Leaks must be repaired within 30 days of adding refrigerant to an appliance over its trigger rate, or 120 days if an industrial process shutdown is required.
Memory tip30 days; 120 with a shutdown.
Source: 40 CFR 82.157(d) (EPA Section 608 rules) · as of 2026
Verification tests
An initial verification test confirms the repair before refrigerant is added back. A follow-up test is done within 10 days of the initial test or of reaching normal operating conditions.
Memory tipInitial, then follow-up within 10 days.
Source: 40 CFR 82.157(e) (EPA Section 608 rules) · as of 2026
Retrofit or retirement plan
If the owner will retrofit or retire instead of repair, a written plan is made within 30 days and the work is finished within one year of the plan's date.
Memory tipPlan in 30 days, done in 1 year.
Source: 40 CFR 82.157(h) (EPA Section 608 rules) · as of 2026
Chronically leaking appliance
An appliance with 50 lb or more that leaks 125% or more of its full charge in a calendar year. The owner must report to EPA by March 1 of the next year.
Memory tip125% → report by March 1.
Source: 40 CFR 82.157(j) (EPA Section 608 rules) · as of 2026
Leak inspections
After exceeding the rate, commercial and industrial appliances with 500 lb or more are inspected quarterly; smaller ones and comfort cooling, once per calendar year.
Memory tip500 lb+: quarterly; others: yearly.
Source: 40 CFR 82.157(g) (EPA Section 608 rules) · as of 2026
HFC leak repair (Part 84)
Since January 1, 2026, appliances with 15 lb or more of refrigerant containing an HFC with a GWP above 53 follow the same 20/30/10 percent rates. Residential and light commercial AC is excluded.
Memory tipHFC threshold is 15 lb, not 50.
Source: 40 CFR 84.106 · as of 2026
Often tested
- Signs of a leak: oil traces and excessive superheat.
- Leak test with nitrogen before charging.
- Calculate the leak rate each time refrigerant is added.
- Leak repair records: keep at least 3 years.
Easy to confuse: Trigger leak rates (per 12 months)
| Appliance type | Leak rate |
|---|---|
| Commercial refrigeration | 20% |
| Industrial process refrigeration | 30% |
| Comfort cooling and other appliances | 10% |
3 sample questions
Verified practice questions from this unit.
Question 1. A comfort cooling system holds 80 pounds of R-22. Above what annual leak rate must the owner repair the leaks?
- ① 30 percent
- ② 20 percent
- ③ 35 percent
- ④ 10 percent
▼ Show answer and explanation▲ Hide answer and explanation
Answer: ④ 10 percent
Key point: Comfort cooling (50 lb+ ODS): 10% trigger
Under 40 CFR 82.157(c), appliances with 50 or more pounds of ozone-depleting refrigerant must be repaired when the leak rate is over 10 percent for comfort cooling (and other appliances), 20 percent for commercial refrigeration, and 30 percent for industrial process refrigeration.
Wrong choices
- 30 percent: 30 percent is the trigger for industrial process refrigeration.
- 20 percent: 20 percent is the trigger for commercial refrigeration.
- 35 percent: 35 percent was an older trigger rate that no longer applies.
Question 2. A supermarket refrigeration system holds 200 pounds of R-22. Above what annual leak rate must it be repaired?
- ① 30 percent
- ② 20 percent
- ③ 15 percent
- ④ 10 percent
▼ Show answer and explanation▲ Hide answer and explanation
Answer: ② 20 percent
Key point: Commercial refrigeration: 20% trigger
Supermarket and cold-storage systems are commercial refrigeration. With 50 or more pounds of ozone-depleting refrigerant, leaks must be repaired when the leak rate exceeds 20 percent per year.
Wrong choices
- 30 percent: 30 percent is the trigger for industrial process refrigeration.
- 15 percent: 15 percent was an older comfort cooling trigger.
- 10 percent: 10 percent is the trigger for comfort cooling and other appliances.
Question 3. Once an appliance is found leaking above its trigger rate, how long does the owner normally have to repair the leaks?
- ① 90 days
- ② 10 days
- ③ 30 days
- ④ 1 year
▼ Show answer and explanation▲ Hide answer and explanation
Answer: ③ 30 days
Key point: Leak repair deadline: 30 days
Under 40 CFR 82.157(d), leaks must be repaired within 30 days of adding refrigerant to an appliance that exceeds the trigger rate, or 120 days if an industrial process shutdown is needed.
Wrong choices
- 90 days: 90 days is not the standard repair period.
- 10 days: 10 days is the time limit for the follow-up verification test, not the repair.
- 1 year: One year is the time to complete a retrofit or retirement plan.
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