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Cooling · RepairAC Refrigerant Leak Repair
AC refrigerant leak repair means finding the hole, fixing it, and recharging by weight, and it runs $300–$800+ depending on where the leak is. An air conditioner is a sealed system and does not use up refrigerant, so a unit that is low is leaking. Topping it up without a repair buys a few weeks or a summer, then the same bill again.
The search uses three methods, picked by how fast the system is losing charge. An electronic detector sniffs along the joints, service valves and coil faces and finds most leaks large enough to matter. For slower ones, the remaining charge is recovered and the system is pressurized with dry nitrogen, then every joint is coated with bubble solution and the gauge is watched for a drop. UV dye is the last resort for a leak that hides: it circulates with the oil and shows under a lamp at a return visit, and it is used only where the manufacturer permits additives.
Leaks turn up in the same places. Schrader cores in the service ports, the same kind of valve as a tire stem, weep once their seals harden. Flare joints on ductless systems and braze joints at the service valves crack from vibration. The evaporator coil develops pinholes in its copper tubes from corrosion, the costliest of the four to fix, and the line set wears through wherever it rubs on masonry or strapping.
Refrigerant work in Ontario is restricted to technicians who hold an Ozone Depletion Prevention (ODP) card, and venting refrigerant to the air is illegal. That is the legal side of why we repair a leaking system and do not top it up year after year; the practical side is that a system running low overheats its compressor and ices its coil. Stop-leak sealants are not used: they can gum up the metering device and contaminate recovery equipment. If you want to know whether the leak itself is a hazard, see is a refrigerant leak dangerous.
The repair depends on the spot. A core is swapped with a tool that keeps the charge in; a joint is cut out and re-brazed with nitrogen flowing through the pipe; a rubbed line is sectioned or replaced. After any opened circuit comes a new filter-drier, a nitrogen pressure test, a vacuum below 500 microns, and a charge weighed in to the nameplate figure plus the line-length allowance. The proof is the superheat and subcooling readings taken with the system running, written on the invoice.
Signs of a refrigerant leak
- Cooling fades over days or weeks, and the system runs longer to reach the same setpoint
- Ice on the large copper line or the indoor coil with a clean filter and open registers
- A hiss or bubbling sound near the indoor coil or along the lines
- Oily residue or a dark stain on a joint, service valve or section of copper
- The system was topped up before and is short again a season later
How it works
If there is ice, switch cooling off and run the fan for a few hours so the coil can be tested. Tell us the unit's age, whether it has been topped up before and when; a system refilled last summer and short again points us at a slow leak.
Pressures, superheat and subcooling confirm the system is low rather than restricted. Then the leak is found with the detector, a nitrogen test or both, and you are shown where it is. The repair price follows the location.
Joint or core repaired, drier replaced, pressure test held, deep vacuum pulled, and the charge weighed on a scale. A final set of readings confirms the charge, and the repaired spot is rechecked with the detector.
Brands: Leak repairs are done on R-410A, R-454B and R-32 systems from Lennox, Carrier, Trane, Goodman, Rheem, Daikin, York, Amana and KeepRite; R-22 machines are assessed before any refrigerant is quoted.
Common questions
How much does it cost to fix an AC refrigerant leak?
Most leak repairs with a recharge run $300–$800+, after a $90–$150 diagnostic that is folded into the repair when you proceed. A leaking Schrader core or an exposed braze joint is at the low end. A leak inside the evaporator coil is not a patch job: the coil is replaced, and that is quoted separately in writing.
Can you just top it up for now?
Not as a plan. Adding refrigerant to a system with a known leak sends that refrigerant to the air a second time and charges you for it twice. In a heat wave we locate and repair an accessible leak at the same visit where we can. If the repair has to wait for a part, we tell you whether the unit is safe to run in the meantime.
Is the leak worth fixing on an older air conditioner?
Under about ten years old with a leak at a joint, core or line, yes. Past twelve with a leaking evaporator coil, compare the coil price with a new system before deciding. On an R-22 unit the refrigerant is reclaimed stock only, so a leak there is usually the end; R-22 air conditioner repair explains the options.
How long does a leak repair take?
An accessible leak is usually found and repaired in one visit of a few hours, most of it spent on the pressure test and the vacuum, which cannot be rushed. A slow leak that needs a standing nitrogen test or dye can take a second visit. An evaporator coil replacement is a longer job, booked once the part arrives.
What does low refrigerant do if I leave it?
The coil runs colder than it should and ices, airflow drops, and the compressor, which relies on returning refrigerant vapour to cool its motor, runs hot. A leak left for a season is a common history behind a failed compressor. Switch cooling off if you see ice, and book an AC repair visit through the contact page.