Diversitech Master Care Leak Armor, HVAC/R Leak Sealant 2oz Permanently Seals and Prevents Leaks in A/C and Refrigeration Systems from 1.5 to 5 Tons

Fill hose was defective and leaked refrigerant from my HVAC unit. This was poorly made. I called Amazon and they wouldn't even take the product back, saying there were restrictions and that the product could not be returned in the mail. Don't waste our money on this one.

My ac unit needs 1-2 pounds added every year and my ac guy wanted to charge me $350 to add this to my ac system. These ac local guys are complete ripoffs. There are honest guys out there, but seriously, I sent him on his way and bought this, following the instructions, turn the ac unit off and leave off about 15 minutes. Then take what you have been sent in this kit out to the outside unit and locate the low side screw fiting. Remove the cap covering it, attach the hose to the can. Tighten. Then screw on the hose with the can attached to your low side fitting. Tighten. Now you need to bleed the air in the line to the top of the can so loosen the hose to the can and your ac unit will vent out. You only need to do this for a second to purge the air out of the line you attached. Tighten back quickly. Leave the can upright and turn the t handle in to pierce the can and then open the t handle to allow the ac unit to charge up the can. You'll hear the refrigerant from your ac system go in the can. (The kit doesn't add refrigerant so ignore the ac guy who tells you to leave this to the professionals, your only adding uv dye and leak sealant only). Once the refrigerant entering the can noise is gone. Turn the t handle clockwise to seal off the can again. Go back inside and turn on the ac unit. Set it cold because you want to run it a minimum of 10 minutes. Go back to Your can, flip it upside down, then open the t handle again allowing the sealant to escape in your ac system. It's yellow in color, and the clear line will turn yellow as it flows out. After 5 minutes to 15 min you'll see the line turning clear again. Once you see this close the t handle clockwise again and remove the line from your ac unit. If Your can still has sealant, you'll have to repeat. If you've done this 3-4 times and it's not taking the sealant, you have more problems then a leak. Could be Freon too low, compressor, ac refrigerant filter clogged, or kink in your refrigerant lines. Good luck. Good hvac guys who won't rip you off are hard to find...

UPDATE: After 2 years, my AC system is still running strong. I have not had to add R22 this year, and I have had zero problems with my air conditioner. Whatever small leak I had was definitely fixed by this product.Easy to install, if you follow the directions and understand how your split AC system works. Like most people here, I had a slow Freon leak that meant every 2-3 years my air conditioner would ice up despite my filter and coils being clean. My dad owned an HVAC company and as a kid I worked with him, so I have a basic understanding of how a split system works, and I can always call him for tech support. Let me just tell you, that if you call an HVAC tech to charge your AC, they are obligated to find your leak first, and try to repair it. Depending on your installation, this could take hours (at $100+ per hour), and they might not find your leak. There are many reasons why they might not find your leak. You could have a microscopic leak that leaks very slowly at a fitting or at the Schrader valve at your charging port only when it is very cold outside. In the summer months with the AC running, the leak my be very small due to the expansion of the copper tubing or rubber O-rings. Additionally, your refrigerant (R22 in my case) carries oil with it throughout the system to lubricate the compressor. Your leak may be small enough that when the compressor is running and the oil is circulating, it will plug the leak. When the compressor stops, it starts to leak slowly under a lower pressure that may be difficult for a sniffer to find. UV dyes work well, but you have to be able to trace all of your copper supply lines from the condenser to the coil. That is time consuming (at $100+ an hour) and difficult if you have a finished basement or an installation where your lines are in a place that is difficult to see.What's an HVAC tech to do? He is obligated to stop you from discharging R22 into the atmosphere. He has a stack of customers waiting for him to get their AC back up and running, and they are all as desperate as you. He's got a family to feed and a business to run. If you have an older R22 unit, he's probably going to recommend that you replace it along with your furnace. He's not trying to rip you off, but he's trying to do what's best for you in the long term. You will be shocked by the bill. A new unit is expensive, R22 now costs over $23 a pound a wholesale, and you have to be licensed to buy it. There are many people and government regulations to blame for that, but it's not your HVAC guy's fault. A quality new 5 ton unit for my house with a higher SEER rating will cost me $7000 at Wholesale cost with me and my dad doing the installation ourselves. Where I live, we run our AC 3-4 months a year. If you go to the DOE website, you will see that for me there will NEVER be a payoff in terms of money saved in efficiency vs installation costs of a high SEER unit over the course of it's expected lifetime.What to do? If you have access to refrigeration gauges and R22, you need to charge your system to it's appropriate level. Once you have done that, you follow the directions that come with this kits (and watch the videos). Make sure you purge the line and charge this can properly. Install this can and run your system for at least 10 minutes (my dad said let it run for at least a half an hour). I know that some people have said that they experienced a compressor lock up after installation. I don't know why this would have happened as a result of this product, if your system was properly charged and you installed it according to the directions. I installed this product two weeks ago and my AC is blowing nice and cold. My leak was so slow that it will be another year or two before I am able to determine how well this stuff seals leaks. I will probably end up replacing my system in the next few years, but in the meantime, my AC is still working great and it only cost me a couple hundred dollars including the R22.

Sealed up my air conditioner. Everything working fine now.

Tried it and it didn't work. Eventually I identified the leak on an outside unit in the aluminum coil. I first noticed it by the oil residue on the ground making the dirt dark. The actual leak was very small but enough to evacuate the system. Even though I could barely see the point of the leak and definitely could not see a actual hole this product did absolutely nothing to seal it. I give it 3 stars as at least after noticing the old residue I was also able to identify the dye from this product was also present. Brazing aluminum is all but impossible, but if you do run into this on your aluminum coil I suggest looking up Dynesic Pipe Seal. It is an epoxy that can bond to aluminum and withstand refrigerant. Only thing is, sand the pipe off real good. I sanded it with a sandpaper that was coarse and made the sanding marks go around the pipe instead of its length. Then, unlike some of the company video's, don't try using a hair dryer. Get a real heat gun and put some heat on this stuff. I had it on at least 800 for enough time to get the pipe and epoxy good and hot. Make sure to leave pipe exposed on both sides of the epoxy so that you can put heat on the pipe as well as the epoxy. The first time I tried this I made the sanded surface too smooth and didn't get things hot enough. It barely held for a couple of weeks and it was a real pain to sand it off to try again. The second time is still holding up after several months. I guess we will find out come next summer.