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Freon leak

have a 20 yr old residential AC system; over past few yrs (and maybe longer) the robustness of the cooling has diminished.

found out it was low on freon and 3 lbs were added (total capaciity is 9 lbs)

freon has never been added to system over 20 yrs till now

what are thoughts on leak (is loss of 3 lbs freon after 20 yrs reasonable?); guess this may mean that leak is minor/tiny

curious if adding 3 lbs may worsen leak via added pressure to system (head pressure was on the low side but not bad)


  • SpenceSpence Posts: 316Member

    So, someone just popped by, said the pressure was low, and added refrigerant?
  • icesailoricesailor Posts: 7,265Member ✭✭✭✭

    Yeah, that's how it usually goes. A few years after I bought my Florida place, the 10+ year  old AC system wasn't cooling and the inside A coil was freezing up. I called some recommended company who sent someone out in an old beater truck with no name on it. It obviously was low on gas/liquid. He put in a few pounds and replaced the missing Schrader valve caps. He could find no leaks but said that the lineset needed to be replaced. That was over 20 years old. Vintage:1982. The old lineset was under the slab and came up 20' away through the floor in the middle of the house. We agreed, and left it that he would run a new line set after we went home the next day. He never came back to do the job. 5 years later, when we moved down here, I called another company that does a lot of work in the community. Someone came, in a truck with the company name plastered all over it and the tech had a shirt with the company logo on it and his very own name on the shirt. He checked the system and said that it didn't need and gas/liquid. He was well dressed, clean and extremely polite. Everything checked out OK. No lost gas.

    I was so impressed with his honesty and the quality of his work that I had them replace the 30 YO ductwork in the attic that was falling apart. They did such a nice and thorough job that I had them replace the whole system. They even put new tamper proof caps on the ports so that the little chips around can't connect a hose on the ports and get baked. Honesty and quality can pay off.

    What I'm saying is that you might need a second opinion. Unlike Massachusetts, in Florida, every time I go to the dentist when I first got here, opening my mouth for an exam was the same as opening my wallet for an inspection to see how much value was in there.

    You may have leaks and need replacements. Did they find a leak? If not, when I waited a few years and the symptoms of a leak didn't appear, I realized that the first guy must have been a frustrated dentist. Working as a sub-contractor on a commission basis.

    If you DO change it to a higher SEER unit, and the unit is quiet, make sure that whatever they replace it is guaranteed to be as quiet as the old one. I had one that was brand I was very familiar with. Reminds me of what the dentist or the first guy wanted to do to me. The new one reminds me of railroads and is just as loud. So loud in fact that if I am watching Television and it comes on, I have to turn up the volume to hear the TV. And when it is off, I can hear a pin drop.

    FWIW, get a second opinion. Unless there is some compelling reason to not do so. Like they showed you a leaking coil or dogs have been marking the condenser case. In my case, the drain trays in the evaporator above the A coil were rusting out and although draining, were allowing condensed water to be thrown back into the air stream and it was making the sheetrock wet at the ceiling registers. Five years ago, it didn't do that.
  • icesailoricesailor Posts: 7,265Member ✭✭✭✭
    edited June 2014
    Popping By:

    It's been my experience that to some companies, that's what a service call entails.

    How much can you check in the allotted 45 minutes with 15 minutes allowed to get to the next service call/annual check up for the advertised  $50.00 annual comprehensive system check up?

    Like the guys who can clean, check and adjust 8+ oil burner/boilers in an 8 hour day.
  • elfieelfie Posts: 264Member
    freon loss - whats normal?

    i guess the question is is it expected to lose freon from a system over 20 yrs (ie. is a perfectly sealed system realistic?)

    and is a loss of 3 lbs over 20 yrs to be expected.

    how many people have original freon after 20 yrs (i would think the oil component within the freon would degrade overtime)

  • Eugene SilbersteinEugene Silberstein Posts: 349Member ✭✭
    Having "NO LEAKS" is normal

    Ideally, system refrigerant should remain in the system and not leak out.... ever.

    However, during the process of routine service, when technicians gauge up on equipment, for example, a small amount of refrigerant is lost. Although this may not be a big deal, over time, the losses can be significant enough to affect the system's ability to cool the space.

    Now, do not think that the three pounds of refrigerant that was lost from the system happened overnight. It was very likely a gradual process that went unnoticed for many years.

    Back in the day when folks like my father walked the earth, air conditioning men sized air conditioners so that, if the homeowner left the front door ajar or left a few windows open, the system would condition the entire neighborhood.

    Having such an oversized system, the unit runs only a short time to satisfy the cooling needs of the space. As refrigerant leaks from the system, the ability of the system to cool the space diminishes, but the homeowner will never be able to tell the difference between a 10 minute unit run-time and an 11 minute unit run time.

    As refrigerant leaks, the run cycles get longer and longer, until the unit runs continuously. At this point, the unit is matching the load on the structure. Now, as the refrigerant continues to leak, the system still runs all the time, but now the unit can no longer meet the cooling needs of the space.

    Now, the homeowner calls for service and the system needs a few pounds of refrigerant.

    So, to address your query. Most refrigerant, in my opinion, in a "sealed" system is lost during the processes of installing and removing gauges from a system.

    On the other hand, there are things called "thermal leaks", which are leaks that are present when the pipes are hot, but "seal" when the pipes cool. These leaks are typically very small and extremely difficult to locate.

    So, a loss of three pounds over 20 years is a beautiful thing and I think we would all sign up for that right now if we could.

    I hope this helps.
  • elfieelfie Posts: 264Member

    thanks for very thoughtful comments

    while i was told 3 lbs were added, its tough to know exactly how much was added

    but at least i saw the gauge reading and it was substantially lower (and still cooled with current freon level)

    the return line now cool and began sweating in a normal manner


  • icesailoricesailor Posts: 7,265Member ✭✭✭✭
    Respectfully weighted:

    Not stepping on the respected Professor, but any time I have seen anyone (and I've seen it a lot) in the last 10 years add liquid to a system, uses a very accurate scale to weigh the cylinder. An electronic scale that might be used by some Latin American drug cartel.

    At the cost of refrigerants today, just "Guessing" is either stupid or someone is going to be ripped off.
  • elfieelfie Posts: 264Member
    a few pounds

    i agree it should be done more precisely to understand exact amt for operation purposes

    i cant get all worked up about 2 3 or 4 lbs (as residential systems are about 6-9 lbs), so if they rip you off its less than a hundred.  i think they approximate within reason.


  • Eugene SilbersteinEugene Silberstein Posts: 349Member ✭✭
    Thanks for "weighing" in

    Not using a scale is not only unethical, it's also illegal.

    Companies are required by law to keep detailed records regarding how much refrigerant is purchased, how much is sold, how much is recovered, how much is accidentally released to the atmosphere, etc. Guessing just doesn't cut it.

    Yes, without using a scale, the equipment owner is most likely getting ripped off.

    I heard of a technician (he actually used to work for us) who charged a customer for 40 pounds of refrigerant, when her PTAC unit only held 2 pounds!

    When confronted, the tech responded to us, "When I got there the pressure was 30 psig and whenI left, the pressure was 70 psig. 70 - 30 = 40. What's the problem?"

    Needless to say, the customer's bill was adjusted and the tech went on to pursue other endeavors.

  • icesailoricesailor Posts: 7,265Member ✭✭✭✭

     "" the tech went on to pursue other endeavors. ""

    His "Other Endeavors" probably involved not using a scale but still did the same work. .

    Something to consider as I think about all this,

    My other Mountain Bike is old and has old tires and tubes. Given time, a lot of time, the tires will go completely flat. My newer bile has a rear tire that will leak slowly over a few months. But still not be flat

    You couldn't find the leaks if someone paid you to do it. But that pressure leaks out to the point that if you remove the tube, it is FLAT. So flat that you can roll it up and put it in a box.
  • elfieelfie Posts: 264Member
    detailed records

    likely consist of a log that bears no reality to activity (except that it all adds up to the weight of freon in the cylinder)

    a very very difficult thing to manage integrity of records that likely exist

    a good control would be to ensure customers are advised of the process controls over freon use/recovery activities

    i did see leakage in the form of white mist that leaked from cylinder  -- oops
  • TonySTonyS Posts: 840Member ✭✭
    Between the kids huffing it

    and jealous neighbors releasing it, it makes sense to just top it off and install a set of locking caps to give yourself a baseline. Then follow it from there. I will spend a little time looking for the obvious but today there are to many variables.
  • dondon Posts: 395Member ✭✭
    No disrespect

    But at 20 years old I would think a new one is in order. Think about it you can spend lots of money chasing a leak. Also what the seer rating on that 20 year old beast? Not to mention poor insulation on the distribution system and lack of mastic tape adding to the cost of cooling that place.

    A lot has change in twenty years may I say for the better. Time to take off that tech hat and put the sales man hat on.
  • icesailoricesailor Posts: 7,265Member ✭✭✭✭
    Git Er' Done:

    It helps to remember that customers have to deal with that they can afford, and if and when they can afford to do it. If ever. And be careful making promises that don't work.

    When I bought my Florida place in 2005, I went up in the attic and all the 1982 ductwork was on the top of the ceiling insulation. I covered it over with R-19 24" insulation batts. It worked as well as it worked. My wife was only there from November to May. When I moved here full time last May (2013), it worked fine. I had records of how much it cost me. On 100 + degree days, it would run and cycle occasionally. I decided to have the 1982 ducting replaced. It was split and falling apart. I read somewhere that it is code to use R-8 in unconfined spaces, that R-6 was for the DIY's that buy from HD & Lowe's. I asked for R-8. You'd have thought I asked for some exotic material for space flight. R-6 was the only thing available and R-8 was a special order item with a long lead time. So.R-6 it is. They insisted that the ductwork had to be "hung up" in an unconditioned attic space. They did a lovely job of hanging all their work up. They also took all the old batts off. I then had them replace the 1996 AC system. Estimated to be lucky if it was 8 SEER because of the age. The new one was 14+ SEER because of space limitations. The new system works great except that my electric bill KWH usage is almost double and the unit never shuts off when it is over 90 degrees OAT. The inside unit is so loud that I have to turn the volume up on the TV so I can hear. And this is considered a quality unit. Well made and designed.

    Last week, I went up in the attic space in the evening (when it had cooled down) and cut all the ductwork down to get it on to the floor that I could reach. I covered what I could with the insulation batts. There is a marked difference in the cooling and time it runs. I know what goes on. It was a first class quality job. If I was some uninformed homeowner, I'd be angry that the money I spent on upgrading my system, is now costing me more for a supposedly more efficient system.

    From some of the DIY/Homeowner experts I see hear, I can hear some of the questions asked to the contractor, who did an excellent job.

    Why does my upgraded and more efficient system cost me more to cool and run longer?

    Why is it better to have a duct hung up off the insulation so that the entire pipe is exposed to the ambient air? Why wouldn't it have been better to have left it on the floor and put the old batts back on?

    And more importantly, the comment about taking your tech hat off and put your sales hat on, why didn't you suggest that I add more insulation to the attic because there are places that it could be improved and it will pay for itself. And that you could coordinate it done (or you do it). You can go to HD or Lowes and rent the blower and buy the blown in insulation.

    Once you answer those questions to the homeowner and customer, do you think they will be calling you  back?

    There's more to sales than just selling something, slamming it in and walking away with a check or credit card receipt.

    Anyone that believes all the crap that the Manufacturers and their Reps tell you is a fool. They're not your friends. No matter how much I try to convince myself that I got a really good job, I'll never convince my wife of that. Especially when I have to go into the attic in June and try to improve the insulation.

    When the AC came on before, it never blew hot air at first. Now, it will blow hot air for 3 or 4 minutes. And we all know why. Tell the wife (or customer) that's normal, and you'll get one of those looks.

    How I always hated that.

    People will afford what they want to afford. But they can't buy something that you don't offer them.
  • dondon Posts: 395Member ✭✭
    Not possible

    Sorry to hear that Ice.I find it hard to believe that they install your system correctly and your power bills double .Key word correctly. The fact you state that your system as you said sound like an airplane speaks volume to an under size distribution system. Why not have someone come out and run a performance test on your system so you will have the number to address with the installer or hvac company that install it and have them make the correction.

    Also as far as people not being able to afford a new hvac system after 20 years of service from the old one I would say they cant afford not to do.
  • icesailoricesailor Posts: 7,265Member ✭✭✭✭
    edited July 2014

    That's not the cause of the noise.

    If you've done any oil hot water boilers, if you do a Weil-McLain WGO/WTGO etc boiler, you can vent them out of the top or out of the back. If you vent out the top, it will be much noisier because the activity of the flame is just below the exhaust. So, venting out the back is quieter because the exhaust has to travel through turns.

    The installs of these places in 1982, has a water heater in a closet with some sort of early hot water recovery unit, like water heat pumps will be now after 2015. The 40 gallon water heater sat on the floor. The fan/coil and heat strip unit sat above the water heater. The cold air went out the top into the duct work in the attic. The duct work in the attic was all replaced and it was actually increased. The noise isn't from the duct work, its from the fan/coil unit. The old unit had the air coming in from the bottom. There were 2 x 4 boards across the closet. The filters were in the bottom. The 14+ SEER unit was the shortest unit they could get in through the door and closet height. I had come up with an idea for gaining height by using steel slats over the water heater and making it as low as I could and still be able to get the water heater out for replacement. The guy had the patience of a Saint. He replaced everything going off the top and all new into the attic. Replacing the crappy low bid connection from 1996. But he also came up with the idea of blocking off the bottom inlet, using the original 2 x 4's, and bringing the air in on the side. The closet has a metal louver door to let the air in. It is the sound of the air and the fan that makes the loud noise. Its more of a resonance sound. If it had come out of the bottom like the old, it would be quieter. When you open the door, and remove the filters, you are looking right in to the inside of the squirrel cage.

    You guys may work on a 20 to 30 Delta T between the inlet and outlet of the ductwork. But, outside the ductwork, Delta T can be as high as 60 or 70 degrees between the OAT in the hot unconfined space and the inside of the cooled air inside the pipe. Heat flows to cold.

    Way back when, when they first used flex duct in the North, I saw places that froze up with running air handlers that had perfect cooled summer air coming out of ceiling registers in January, and perfect heated air in the Summer. I just didn't know how effective my covering the new duct in the attic had been.

    Many have no clue how much insulation can make a difference.

    Thanks for your interest.
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