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  1. #1
    Join Date
    Oct 2012
    Posts
    8

    Replace whole system due to refrigerant leak?

    With some recent chilly weather we turned on our heat pump about 2 weeks ago and noticed that it was short cycling (turning on for ~30-40 seconds then turned off). We called a local HVAC company, they came out and found that the pre-filters were completely clogged. They were cleaned and returned, and all appeared normal. But that night it started short cycling again. HVAC company returned and now says our system has a refrigerant leak (determined by low pressure), either in the heat pump, furnace, or somewhere in between. He isn't sure where it's located or how slow or fast the leak is but he is betting that it's in the coils of either the heat pump (less likely) or the furnace (more likely) and said that he recommends replacing the whole system. He added some refrigerant to hopefully hold us for a while. The system has been off ever since (~3 days ago) because the outside temp has been warm.

    We replaced the heat pump in 2007 (Bryant) and the furnace (Trane) is from the late 1990s (not sure). The HVAC company also said that we shouldn't have mismatched pieces, they should be the same brand (the company who installed it said it didn't matter, though they're now out of business).

    He also said we can't replace just one part, it has to be all or nothing because apparently the type of refrigerant used in new systems is different from older systems and not compatible.

    So...before we consider replacing the whole system, I just need to know is this information accurate, is there anything else that we can do to avoid replacing the whole system? Is it worthwhile to have him actually find the leak to determine if it's fixable?

    Thanks for any help!

  2. #2
    Join Date
    Aug 2007
    Location
    Northern VA 38 degrees N by 76 degrees W
    Posts
    5,060
    Quote Originally Posted by jkshots View Post
    With some recent chilly weather we turned on our heat pump about 2 weeks ago and noticed that it was short cycling (turning on for ~30-40 seconds then turned off). We called a local HVAC company, they came out and found that the pre-filters were completely clogged. They were cleaned and returned, and all appeared normal. But that night it started short cycling again. HVAC company returned and now says our system has a refrigerant leak (determined by low pressure), either in the heat pump, furnace, or somewhere in between. He isn't sure where it's located or how slow or fast the leak is but he is betting that it's in the coils of either the heat pump (less likely) or the furnace (more likely) and said that he recommends replacing the whole system. He added some refrigerant to hopefully hold us for a while. The system has been off ever since (~3 days ago) because the outside temp has been warm.

    We replaced the heat pump in 2007 (Bryant) and the furnace (Trane) is from the late 1990s (not sure). The HVAC company also said that we shouldn't have mismatched pieces, they should be the same brand (the company who installed it said it didn't matter, though they're now out of business).

    He also said we can't replace just one part, it has to be all or nothing because apparently the type of refrigerant used in new systems is different from older systems and not compatible.

    So...before we consider replacing the whole system, I just need to know is this information accurate, is there anything else that we can do to avoid replacing the whole system? Is it worthwhile to have him actually find the leak to determine if it's fixable?

    Thanks for any help!
    Mixing brands is not a big issue in most cases. I first would call a different company, if they felt there was a leak they should have given you the option of looking for it, and the system should have been checked on the first visit when the pre-filters for the EAC where cleaned.

    If it is a condensing furnace the secondary coil is probably dirty, if its an atmospheric vent the evaporator is probably dirty. Just the age of your equipment does not warrant replacement without first determining what if anything is in need of repair.

    Look in the dealer index on this site and post your location and perhaps there is some one in your area.

  3. #3
    Join Date
    Jan 2001
    Location
    Pamnyra VA.
    Posts
    710
    The only way to find a leak is to isolate the outdoor unit,the copper lines and the indoor section separetaly and fill them up with nitrogen.Costly yes but might help you out.

  4. #4
    Join Date
    Jun 2007
    Location
    Greenwood Indiana (Indianapolis)
    Posts
    420
    When you say the furnace is a Trane, does this mean that it is a gas furnace or could it be an electric furnace? Need to know to answer your question. And you don't have to isolate the system to determine where the leak is. There are some very sensitive leak detectors that can locate most all leaks, usually in a short period of time. There has only been a couple of times where I had to separate the system to determine where the leak is. If it is a gas furnace, then the indoor part of the heat pump is probably a Bryant coil and is the same age as the outdoor unit.
    As iron sharpens iron so one man sharpens another Proverbs 27:17 NIV84

  5. #5
    Join Date
    Aug 2012
    Posts
    2,663
    Quote Originally Posted by skibme View Post
    The only way to find a leak is to isolate the outdoor unit,the copper lines and the indoor section separetaly and fill them up with nitrogen.Costly yes but might help you out.
    Really, the only way?

  6. #6
    Join Date
    Aug 2012
    Location
    North Dakota
    Posts
    518
    sounds like a comission based service tech. answer to me sell new equipment instead of a repair job. Better get another contractor out to get a fresh start most leaks are easy to repair when found (slow leaks are usually on low # side of the system) inside ??
    An 07 a/c sure shouldn't need to be replaced yet? though if it does ? do your homework get quotes ,check out the companies and the manufactures talk w/friends and niebors,get refrences

  7. #7
    Join Date
    Oct 2012
    Posts
    8
    Kevin Weaver - The whole system is electric, not gas.

  8. #8
    Join Date
    May 2000
    Location
    Indianapolis, IN, USA
    Posts
    34,173
    Putting the Bryant on the old air handler is a problem and a mismatch. And is likely the problem. The indoor coil is very often where the leak is. A good tech that doesn't have commission on his mind could whip out a leak sniffer and confirm rather quickly where the leak is. Only if he can't find it on accessible piping and coils is a nitro isolation needed.

    If the indoor is the culprit, a new air handler will work just fine IF the metering device (expansion valve most likely) is sized or designed for R22. A matched Bryant/Carrier unit would be the best bet. They come with a R410 valve but would then be changed to a R22 valve and be just what you need.

  9. #9
    Join Date
    Aug 2012
    Location
    North Dakota
    Posts
    518
    my bad got mixed up w/other post

  10. #10
    Join Date
    Jul 2006
    Location
    Virginia
    Posts
    4,665
    i would hard at the 1990s trane air handler for the leak . if it is leaking at the indoor unit then replace the complete indoor unit with a matched unit for the outdoor unit.
    We really need change now

  11. #11
    Join Date
    Jul 2010
    Location
    nebraska
    Posts
    1,629
    As the guys have said there's no need to replace the whole system. Step one is find the leak with an electronic detector. Once you know for sure where it is then a decision can be made to replace or repair a component. I wouldn't advise spending any money on a 20 year old air handler,if that's where the leak is.

  12. #12
    Join Date
    Oct 2010
    Location
    Anderson, South Carolina, United States
    Posts
    7,041
    Since the outdoor unit is only 5 years old I would find the leak, probably on indoor coil. If so I would get a matched air handler for your outdoor unit and put a r22 txv on it and you're good to go and will save approx half of what you would spend on a complete system

  13. #13
    Join Date
    Jun 2001
    Location
    Moore, Oklahoma, United States
    Posts
    4,280
    My own system had a leak in the evap coil. It was 13yrs old and oversized, so I just put in a whole new system. Switching to 410A will reduce the cost of any refills it may need over it's lifetime.

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