ARS Rescue RooterAir Conditioning, Heating, Indoor Air Quality, Plumbing, Drain Cleaning & Sewer Lines

How do you check for a coil leak? How much are the repairs and will they add Freon for the unit that's read low?

Patricia, Fort Worth, TX

The question is, how do we know it’s the coil leaking? Well, there several ways to check for a refrigerant leak.
1) An electronic refrigerant leak detector is the most commonly used tool. This tool is used by running the detector along the refrigerant components unit it picks up any signs of refrigerant. If such a sign is detected, the refrigerant leak detector alerts the technician.
2) Some technicians use nitrogen with a Freon tracer if the leaks are hard to locate. With nitrogen you can increase the pressure in the system and by adding more pressure. This is a useful tool, however leaks are easier to find with the electronic leak detector.
3) An isolation test is used if the leaks cannot be found by the first two mentioned above. Using this method depends on how the air conditioning and heating equipment is installed. For example: Let’s say that the outdoor unit and the indoor unit have been checked, no leaks were found and the line set that connects the two are enclosed in the interior walls. By cutting the line set at the outdoor and indoor unit we can isolate the refrigerant components separately. We then use nitrogen to ensure that the outdoor unit, indoor unit and the line are all set at equal amount of pressure. If you suspect a very small leak, this may have to sit for several days. A few days later, we return and check for a pressure drop in each of the three components. The results will give us idea of which component the HVAC technician should concentrate on. This works extremely well is the line is set within walls, since we never want to make holes in the wall without knowing if the leak is truly behind the wall or not.
4) Another method to detect a Freon leak to run a dye test. With this method a dye is added to the system and the unit will continue to operate until the dye has circulated throughout the refrigerant system. If there is a leak in the refrigerant system, the dye will appear with the use of a black light. This glowing effect alerts the technician to where the leak is.

While these are the most common methods used to detect refrigerant leaks, these are only some of the leak tests available today. The cost of repairs will vary depending on the coil size, location and the availability of the manufacturer’s coil if it needs to be replaced. But most importantly you need to determine if the leak can be repaired. I suggest that you ask your technician if the leak is under any type of warranty. Why add Freon to a leaky system it will just leak out again in time? I hope this information helps. If you would like for an ARS/Rescue Rooter technician to perform one of these leak tests for you, you can contact your local branch at (817) 222-1211.