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What way is least costly/best way to find a Freon leak in Central AC?

Hi..I have a Ruud central AC 16 SEER put in around 2011 or 2012..
We have Two Units 4 Tons Each.
Blowers in Attic..The other things(forgot what they call them) outside in back of house with new lines.
The one that Cools the parts of the house we occupy has always worked.
The other which is for the other part really has never worked (probably) since it was installed.
That Unit we never really needed to turn on but when we did on the very hottest days..we realized
it didnt do much cooling. after a few years we realized the thing doesnt blow cool air at all..just blows air
like a fan.So a friend of my brother in law came by checked and said.."low on freon" filled it put a pin in and said likely was a leak there and off he went.
Seemed to cool some.,so we were happy that it was ok but didnt really use it.
This year we turn it on ..no coolness only air.
Im guessing Freon is leaking basically in an unused 6-7 year old unit.
How is a leak found in such a situation?
Many thanks.


    EBEBRATT-Ed Member Posts: 15,829
    a qualified service technician with an electronic leak detector.

    find the leak
    fix the leak
    leak test
    install new filter dryer
    evacuate air and non condensables
    recharge with refrigerant

    if your lucky maybe done in 3-4 hrs

    then again if it never worked right their may be other issues
  • Leonard
    Leonard Member Posts: 903
    edited July 2018
    If it's a real big leak outside .....soap and water in a squirt bottle looking for bubbles . Check joints first. ( but that type of leak would leak down ~ about the full charge over about a 1-2 weeks ). On cars loose ~ 1/3 the gas charge and you don't get any real cooling.

    Unscrew plastic dust caps on pressure test ports, do you hear gas come out as you unscrew cap?

    For regular leaks likely get an AC guy, they have very sensitive electronic sniffers, hand held. Very nice tool to hunt down leaks, but not a cheap tool.

  • Solid_Fuel_Man
    Solid_Fuel_Man Member Posts: 2,646
    You can look around the lines and in the outdoor (condenser) for what would appear to be oil residue. Most likely you won't see much, you'll need to have a licensed pro and he will check for any pressure remaining in the system. Then recover and pressurize with nitrogen to 150 psi or so and look for leaks with a soap and water solution from a spray bottle.

    At that point, one can determine the cost and scope of the repair and give you an informed decision from there. Expect to pay for an hour or two labor to find the leak. More depending on the accessibility of the lines and attic unit (evaporator).
    Serving Northern Maine HVAC & Controls. I burn wood, it smells good!
  • Dave0176
    Dave0176 Member Posts: 1,177
    edited July 2018
    @Athana said What way is least costly/best way to find a Freon leak in Central AC“

    Bacharach H10, that’s all I use, finds then all the time. Little expensive though lol.
    DL Mechanical LLC Heating, Cooling and Plumbing 732-266-5386
    NJ Master HVACR Lic# 4630
    Specializing in Steam Heating, Serving the residents of New Jersey


    I cannot force people to spend money, I can only suggest how to spend it wisely.......
    IronmanHarvey Ramer
  • ratio
    ratio Member Posts: 3,696
    Best way is to call a quality (Not necessarily the most expensive!) service guy. Cheapest would be a bottle of leak detection solution (not soap).
  • Leonard
    Leonard Member Posts: 903
    edited July 2018
    System circulates pump lube oil with the "Freon", easiest to look for oil leaks, areas you can see.

    Yes forgot about UV dye, you add it to the system. Make sure it's comparable with refrigerant gas in your system. There are several refrigerant gases, don't want to mix them.

    Don't let any water or air into system or the moisture reacts with the gases and heat to make acids that eventually attack $$$$ pumps, valves ..... Have to add dye on low pressure side or dye container (can, etc... ) could burst. (think grenade, while running hi side pressures can be over ~ 250+ psi).

    When I needed a UV light, I took a 18 inch blacklight I had and wired long 115V vac cleaner power cords onto bulb so I would have a wand. I used a GFI for safty. Careful, I think the ballast kicks off ~ 750 volts during starting. Now days they sell small UV led flashlights, more convenient.
  • Ironman
    Ironman Member Posts: 7,397
    Ironman said:

    "Least costly/Best way". Those two don't ride the same train together.

    I think that I'm gonna re-phrase that and say: "when you do something the best way, it WILL be the leas costly in the long run".
    Bob Boan
    You can choose to do what you want, but you cannot choose the consequences.
    Harvey Ramer
  • GBart
    GBart Member Posts: 746
    How is a leak found in such a situation?

    Call a technician, have him find it, repair it, open wallet.- sarcasm

    Seriously sounds like it never worked, probably faulty/poor installation. Don't run it, you could be sucking in atmosphere (non condensables) and moisture and our systems don't like that.

    You can't find a leak when it's low either, you could look around for oil around the copper piping, fittings, joints, anywhere there is oil there is likely a leak because the compressor oil goes through our system and will come out where a leak exists.
  • Athana
    Athana Member Posts: 105
    Thanks everyone..does the freon reside in a big way inside the Blower in the attic..or just in a section of the Blower..(.ie easy to test).
    Also can one readily isolate where the leak is in general (Line..Condensor..Blower)
  • Athana
    Athana Member Posts: 105
    edited July 2018
    P.S That friend of my brother in law which I mentioned did come with his Leak detector looked around and didnt really notice anything(but he didnt check the line going up to the attic as its covered with that black rubbery insulating cover and he didnt have a ladder.But scanned the Condenser..exposed line in attic up to the Blower (but I dont think he opened blower).
    He thought it may be the pin where Freon goes in and put a new one in..charged it said it was low by about 7 lbs..seemed to cool..but when I needed to use it a month later warm air.
  • ratio
    ratio Member Posts: 3,696
    Unless you had extra valves put in when the system was installed, there aren't many parts that can be isolated. The refrigerant is in the outdoor unit, indoor unit, and the two copper pipes that connect them.

    You really would be much better served by calling a professional. Even if you do locate one or more leaks, a proper repair uses tools that could easily cost a thousand dollars or more.

    Try the Find a Contractor link at the top of the page.

  • Athana
    Athana Member Posts: 105
    Yes..Im really not asking these questions to do any of this myself..just to educate my self and not be completely in the dark.If there was a trustworthy well priced person that I knew, I would be asking these questions only to help with some suggestions..but since we lost our friend JStar and his mate Edison (which we found here)we are lost, and make too little money now to comfortably have an open wallet.
    Im in Hillside NJ(next to Newark) I hope we can find a fair indie person again.
    HVACNUT Member Posts: 5,887
    Where I work, a lot of times the refrigerant lines run underground forever or in exterior walls. If I dont see a leak in an exposed area, I use a sealant. It used to have a problem gumming up TXV's, but that seems to have been solved.
    On a ductless system though, find and fix the leak.
  • Athana
    Athana Member Posts: 105
    > @EBEBRATT-Ed said:
    > a qualified service technician with an electronic leak detector.
    > find the leak
    > fix the leak
    > leak test
    > install new filter dryer
    > evacuate air and non condensables
    > recharge with refrigerant
    > start-up
    > if your lucky maybe done in 3-4 hrs
    > then again if it never worked right their may be other issues

    Sounds good..let's do it ..: )
  • clammy
    clammy Member Posts: 3,113
    Your service provider should have removed the a /h doors and check the evaporator ,the txv and line set .I recently had a service call w similar issues the last guy did the same added freon and bs .I ended up find the leak on the txv i reclaimed repaired and vacuumed the system took me a couple of hours the last guy was back twice year to put Freon in .As for stop leak the ho asked if i could use this to solve his issues after seeing a flammable insignia on the product i refused to use feeling that without proper labling to let others know the system had this product in it.It seems that there are alot of semi older system that have convertable evaps that a expansion valve change out from either 410 to 22 or vise versa seems to be the issue .Also that if the original installer had done a proper pressure and leak test and check his braze joints there would be one issue . For myself i try my best to only have 4 joints on my installs 2 at condenser and 2 at the ah and any other joints that i need to do are usually marked conspicuously for the future .Just way to many under educated installer out there peace and good luck clammy
    R.A. Calmbacher L.L.C. HVAC
    NJ Master HVAC Lic.
    Mahwah, NJ
    Specializing in steam and hydronic heating
  • mikeg2015
    mikeg2015 Member Posts: 1,194
    Cheapest way to “Find” the leak? Looks for oil on lines or oil spot on a coil. Refrigerant has oil vapor in it to lubricate the compressor.

    Congrats, you found it. Now hire someone to repair it.
  • Harvey Ramer
    Harvey Ramer Member Posts: 2,261
    Whatever you do, don't use soap and water. Many soaps are alkaline based and are corrosive to copper.

    When I have a leak, I give it a quick visual first. I find, perhaps about 30% of leaks by the oil residue.
    If I strike out on that method, the H10 is the next go to. There are only a few contrary ones that will slip past the H10.
    For the contrary few, I carry dye as a last resort.

    Depending on the age of the system, the leak location and the leak size, I'll use Easy-Seal, which has been good to me so far.