Home › Commercial Refrigeration Guide › Walk-In Cooler & Freezer Guide › Walk-In Refrigerant Leak Detection and Repair
Updated October 14, 2026
Quick answer
A refrigerant leak slowly robs a walk-in of capacity: longer run times, partial frost, a warm box. The fix is to find and repair the leak, then recharge, not to "top off." Since 1 January 2026, federal rules require leak rate calculations and repair within 30 days for commercial refrigeration appliances holding 15 pounds or more of HFC refrigerant that leak 20% or more a year.
Signs of a leak
- The box takes longer to cool or will not reach setpoint.
- The compressor runs much longer than it used to.
- Frost on only part of the evaporator coil.
- Oily spots on tubing, fittings or coils.
- Bubbles in the sight glass, if your system has one.
- A technician has added refrigerant more than once.
How leaks are found
| Method | Used for |
|---|---|
| Electronic leak detector | Sniffing joints, valves and coils |
| Bubble solution | Pinpointing a suspected joint |
| Nitrogen pressure test | Proving the system holds pressure after repairs or when the leak is hard to find |
| UV dye (where approved by the manufacturer) | Slow leaks that are hard to catch |
| Ultrasonic detector | Leaks in noisy or windy places |
Common leak points on walk-ins include flare fittings, Schrader valve cores, vibrating tubing at the condensing unit, evaporator coil return bends, and corroded condenser coils.
The repair
- Recover refrigerant from the affected section as required by EPA rules.
- Repair the leak: braze the joint, replace the valve core, or replace the coil.
- Pressure test with nitrogen and evacuate to a deep vacuum.
- Recharge to the correct charge and check superheat and subcooling.
- Verify the repair and record the refrigerant added.
Federal leak repair rules (from 1 January 2026)
EPA's Emissions Reduction and Reclamation rule (40 CFR 84.106) covers appliances with 15 pounds or more of refrigerant containing an HFC or certain substitutes. For commercial refrigeration:
- A leak rate must be calculated each time refrigerant is added.
- If the leak rate exceeds 20%, the leak must be identified and repaired within 30 days of adding refrigerant.
- Initial and follow-up verification tests are required for each repair.
- Appliances that keep leaking above the threshold need leak inspections (once a year for 15–499 lb systems; quarterly for 500 lb or more) until they stop leaking.
- If you choose to retrofit or retire instead of repairing, a plan is due within 30 days and the work generally within one year.
- Appliances that leak 125% or more of their full charge in a calendar year must be reported to EPA by 1 March of the next year.
- Records must be kept for three years.
Many single walk-ins hold less than 15 pounds of refrigerant and are outside these rules, but larger and remote systems often exceed it. Appliances using substitutes with a GWP of 53 or below are not covered. Your technician should tell you the full charge of your system.
Repair or replace a leaking system?
A single repaired joint is routine. Repeated leaks in a corroded coil, or a system on R-404A that needs frequent recharges, are often a reason to compare repair with replacement. Existing systems can still be repaired; EPA's new refrigerant limits apply to new installations. See R-404A retrofit or replace.
Owner checks that help find leaks faster
- Note when you first saw longer run times or warmer readings.
- Look (without touching) for oily stains on tubing, fittings and coils.
- Check service records for refrigerant added before.
- Note whether the problem is worse on hot days.
Bay Area and California notes
California's CARB has its own refrigerant management rules for larger systems, with registration, leak inspection and reporting requirements that apply on top of federal rules. If your facility has large refrigeration systems, ask your technician whether CARB requirements apply. For a single small walk-in, federal rules and good practice are usually the main concern: find the leak, fix it, and keep records.
What not to do
- Do not accept repeated "top-offs" without a leak search.
- Do not let anyone vent refrigerant; it is illegal.
- Do not ignore oily spots on tubing.
- Do not assume a small walk-in is exempt from all rules; good practice still applies.
Owner records
Keep each service report that shows refrigerant added. Those records show your leak rate over time and are required for larger systems.
When to call a technician
Call if your walk-in has needed refrigerant before, or shows long run times and partial frost. Adding refrigerant without fixing the leak wastes money and, on larger systems, can breach federal rules.
Open 7 days, 8 AM to 5 PM, with emergency service until 9 PM. CA Lic. #776244.
Frequently asked questions
Can you just add refrigerant to my walk-in?
Adding refrigerant without finding the leak only delays the next failure. For systems covered by EPA leak rules, repair is required when the leak rate is too high.
How do I know how much refrigerant my walk-in holds?
The full charge is on the condensing unit nameplate or in the service records. Ask your technician to note it.
Do EPA leak rules apply to my small walk-in?
Only if the appliance holds 15 pounds or more of covered refrigerant. Many small self-contained units hold less.
What is a chronic leaker?
An appliance with 15 pounds or more of refrigerant that leaks 125% or more of its full charge in a calendar year. The owner must report it to EPA by 1 March.
Who can repair refrigerant leaks?
Only EPA Section 608 certified technicians may open refrigerant circuits.
How long does a leak repair take?
Simple leaks can be fixed in a visit; hidden leaks and coil replacements take longer.
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