Leak Detection, Repair, and Recordkeeping for Low-Pressure Appliances
Leak detection and repair questions test the 50-lb threshold, the correct leak-rate threshold, repair deadlines, verification, and three-year records. Low-pressure chillers often hold well over 50 lb, so the Section 608 leak repair rules usually apply.
Core rules
- The leak repair rules apply to appliances containing 50 lb or more of refrigerant. Classify the appliance by end use: comfort cooling has a 20% annual leak-rate threshold; commercial refrigeration and industrial process refrigeration have 35%; other appliances have 15%.
- Calculate the annual leak rate as refrigerant added over a 12-month period divided by the appliance’s full charge, then convert to a percentage. Do not use the amount recovered at one service call unless it represents the annual addition.
- If the threshold is exceeded, the owner must repair the leak within 30 days, with limited documented extensions for parts or shutdown constraints. Industrial process refrigeration may have additional time if a shutdown is required.
- After repair, perform a verification test. If the repair fails verification, repair again or develop a retrofit/retirement plan. Chronic leakers may be required to retrofit or retire by a specified deadline.
- Keep records for at least three years: refrigerant added, leak inspections, repair dates, verification results, and the leak-rate calculation. Technicians must give the owner the information needed to keep compliant records.
- Use electronic leak detectors, soap bubbles, ultrasonic detection, or pressure-decay methods. Never use an open flame. For low-pressure equipment, nitrogen pressure testing must stay within design limits.
Worked example
A 1,000-lb R-123 comfort-cooling chiller has 210 lb of refrigerant added over 12 months. Leak rate = 210 ÷ 1,000 = 21%. The comfort-cooling threshold is 20%, so the owner must repair the leak within 30 days, verify the repair, and keep records. If the same chiller were industrial process refrigeration, 21% would be below the 35% threshold, so the mandatory leak repair trigger would not be met-though the venting prohibition and good-faith repair obligations still apply.
Traps that cost marks
- Using 15% for every appliance instead of classifying by end use.
- Forgetting the 50-lb applicability threshold.
- Failing to annualize the leak rate.
- Skipping verification after repair.
- Keeping records for one year instead of three.
- Treating a below-threshold leak as permission to vent.