A Leak Rate Just Came Back Hot. Now What? The Complete Repair Workflow Under Subpart C

You followed the process. Your tech weighed the refrigerant, recorded the exact quantity, and calculated the leak rate before leaving the site. The number came back above the threshold.

Now what?

This is the moment where compliance shifts from documentation to action — and where the regulation gets specific about what must happen, in what order, and by when. If you've been following along with this series (the 15-pound rule, how to calculate leak rates, Subpart B vs. C confusion, documentation mistakes), your records are solid. This post is about what happens next.

Let's walk the entire workflow, step by step, using a real-world scenario.

The Scenario

Tuesday, January 20. Your tech is on a service call at a strip mall in your area. One of the rooftop units — a 22-pound R-410A system providing comfort cooling for a dental office — is running warm. The tech weighs in 4 pounds of refrigerant.

He pulls the service history (full charge: 22 lbs, last addition: none since Subpart C started, so this is the first calculation). Using the Annualizing method with the 365-day substitution for first calculations:

(4 ÷ 22) × (365 ÷ 365) × 100 = 18.2%

The equipment category is comfort cooling. The threshold is 10%.

The leak rate is 18.2%. The threshold has been exceeded.

A 30-day clock just started.

Step 1: Identify and Repair the Leak (Days 1–30)

The regulation is clear: once refrigerant is added and the calculated leak rate exceeds the applicable threshold, the owner or operator must identify and repair all leaks within 30 days (§ 84.106(d)).

A few critical details here:

The clock starts when the refrigerant is added. Not when the office processes the ticket. Not when the building owner gets the report. The day the tech tops off the system and the calculation exceeds the threshold — that's Day 1. In our scenario, Day 1 is January 20.

The repair must be done by a certified technician. All repairs under Subpart C must be conducted by a technician with EPA Section 608 certification (§ 84.106(d)). This is the same certification your techs already hold — but it's worth confirming, because it's a separately citable violation if the person doing the repair isn't certified.

All leaks must be identified and repaired. Not just the obvious one. Not just the one your tech thinks is the problem. All visible and accessible components should be inspected as part of the leak identification process.

The 30-day window is for everything: finding the leak, repairing it, and completing the initial verification test. Don't spend 25 days chasing the leak source and then realize you still need to verify the repair.

For our dental office rooftop unit, the most likely culprits on a unit this size: Schrader valve cores, flare connections, service valves, and the condensing coil — especially if the unit has been up on the roof for a few years taking weather. Your tech should be doing a systematic inspection with an electronic leak detector and/or UV dye, documenting every component checked and what was found.

Step 2: Initial Verification Test (Within the 30-Day Window)

Once the repair is complete, you can't just walk away. The regulation requires an initial verification test to confirm the repair actually stopped the leak (§ 84.106(e)).

The initial verification test must be performed before any additional refrigerant is added to the appliance. This is key — you repair the leak, then you verify the repair under the existing conditions. You don't recharge first and then test.

What counts as a verification test? The regulation doesn't specify a single method, but the test must demonstrate that the repaired leak(s) are no longer leaking. Common approaches include standing pressure tests, electronic leak detection at the repair site, and nitrogen pressure decay testing. The method should be appropriate for the type of leak and the repair performed, and the results must be documented.

Step 3: Follow-Up Verification Test (Within 10 Days)

After the initial verification test passes, there's one more step: a follow-up verification test, which must be conducted after the appliance has returned to normal operating characteristics and conditions (§ 84.106(e)).

The follow-up test confirms that the repair holds under real-world operating conditions — thermal cycling, vibration, pressure changes, and everything else a running system experiences. A repair might pass a static pressure test but fail once the compressor cycles and the unit goes through its normal temperature and pressure swings.

The regulation requires this follow-up test to be conducted within 10 days of the initial verification test.

For systems with a full charge of 200 pounds or more, the follow-up verification test is mandatory. For smaller systems — like our 22-pound rooftop unit — the regulation under Subpart F historically required it for 50+ pound systems. Under Subpart C, best practice is to treat verification testing as mandatory for any system that triggered a repair, regardless of charge size. The documentation protects you either way.

Here's the timeline so far for our dental office unit:

Step 4: Ongoing Leak Inspections

Here's the part most contractors don't realize: a successful repair doesn't end your obligations. Once an appliance has exceeded the applicable leak rate, it enters a mandatory inspection schedule that continues until the system demonstrates it's consistently below the threshold (§ 84.106(g)).

The inspection frequency depends on system size and type:

For our 22-pound rooftop unit, this means an annual leak inspection is required until the system demonstrates a leak rate below 10% on its next calculation. The inspection must cover all visible and accessible components and be conducted by a Section 608-certified technician.

This is where the repair creates a follow-on service obligation. If you're the contractor who did the repair, this is an opportunity to set up ongoing monitoring. If you're not, the building owner still needs to ensure it happens — and documenting that you informed them of this requirement protects both parties.

The Branching Path: What Happens When the Repair Fails

Everything above assumes the repair works. But what if it doesn't? What if the initial verification test fails, or the follow-up test shows the leak is back?

This is where the regulation creates a branching decision tree, and the stakes get higher.

Path A: Retry Within the 30-Day Window

If the initial verification test fails, you can make additional repairs and retest — as long as you're still within the original 30-day window. There's no limit on the number of repair attempts within that window. You can repair, test, fail, repair again, test again, as many times as you can fit in 30 days.

The key constraint is time. Day 30 is a hard boundary. If you're on Day 28 and the second repair attempt also failed, you have two days to get it right or you're moving to Path B.

Path B: Retrofit or Retirement Plan

If repairs fail to bring the leak rate below the applicable threshold within 30 days, the owner or operator must create a retrofit or retirement plan within 30 days of the original threshold exceedance date (§ 84.106(h)).

Let's be precise about what this means:

Retrofit means converting the appliance to use a different refrigerant. The plan must include records of the repair of all identified leaks and an itemized procedure for the conversion — what changes are needed for compatibility with the new refrigerant, what components need replacement, and a schedule for completion.

Retirement means taking the appliance out of service. The plan must include a schedule for removal and replacement.

The plan must meet these requirements:

• Signed by an authorized company official
• Dated
• Accessible at the site of the appliance (paper or electronic)
• Available for EPA inspection upon request
• Completed within one year of the plan's date

For our dental office scenario, a retrofit or retirement plan on a 22-pound rooftop unit probably means replacement. A 22-pound comfort cooling system with a leak that can't be repaired within 30 days is likely at end-of-life. The building owner needs to know this, and they need to know it early — not on Day 29 when the clock is almost up.

Path C: Extension Requests

In certain cases, the 30-day repair deadline can be extended:

• Components unavailable: If a necessary repair part is not available, the deadline extends to 30 days after receiving the component, but not to exceed 180 days total.
• Regulatory conflict: If other applicable federal, state, or local regulations make the repair within 30 days impossible, extensions may be granted.
• Industrial process shutdown required: The repair window extends to 120 days.

Note what is not a valid reason for extension: "I couldn't find a certified technician." That's not an acceptable basis for delay. Schedule accordingly.

The Complete Decision Tree

Here's the full workflow in one view:

What This Means for You as the Contractor

Here's the reality check. Subpart C puts the legal obligations on the owner or operator of the equipment — typically the building owner or property manager. But the contractor is the one in the field doing the work, generating the documentation, and making the recommendations.

If you're a small HVAC contractor servicing commercial buildings, your role in this workflow is critical at every step:

At detection: You're calculating the leak rate. You're the one who knows the number exceeded the threshold. Communicate it clearly and in writing to the building owner, along with the 30-day repair requirement. Don't assume they'll figure it out.

At repair: You're performing the repair and the verification tests. Document everything — the leak location, the repair performed, the test method, the result. This documentation protects the building owner and you.

At the decision point: If the repair fails, the building owner needs to know their options immediately. Be the contractor who lays out the paths clearly: retry the repair, plan a retrofit, or plan a replacement. Don't wait until Day 28 to have this conversation. If you suspect the repair won't hold — age of the equipment, condition of the coils, history of prior leaks — say so on Day 1.

For ongoing inspections: Offer an annual inspection service specifically for systems that have triggered threshold exceedances. This is a new revenue line item that didn't exist a month ago, and the regulation creates the demand for it.

The 30-day repair clock is the building owner's obligation. The 30-day repair clock is your opportunity. The contractor who manages this workflow proactively — communicating clearly, documenting thoroughly, and offering the next step before the customer asks — becomes irreplaceable.

The Records You Need for Every Repair

Before we wrap up, here's the documentation checklist for every repair triggered by a threshold exceedance. All records must be retained for at least three years:

• Date refrigerant was added and leak rate calculation (showing it exceeded the threshold)
• Leak rate value and method used (Annualizing or Rolling Average)
• Full charge value used in the calculation
• Equipment category and applicable threshold
• Date(s) of leak inspection and locations checked
• Leak location(s) identified
• Description of repair(s) performed and date(s) completed
• Initial verification test: date, method, and result
• Follow-up verification test: date, method, and result
• Communication to owner/operator documenting the exceedance and repair requirement
• If applicable: retrofit or retirement plan with all required elements
• If applicable: extension request documentation

That's a lot of fields. It's also exactly what an EPA inspector will ask for. Having all of it in one place, organized per-appliance, is the difference between a routine audit and a nightmare.

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Next Monday, we're shifting gears to talk about what Subpart C means for the conversations you're having with building owners — how to explain the new requirements, frame the costs, and turn compliance into a competitive advantage. See you January 26th.