Is New Compressor Needed? - Page 2
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  1. #14
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    May 2005
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    midwest USA
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  2. #15
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    May 2005
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    midwest USA
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    Quote Originally Posted by udarrell View Post
    My quoted post above needs some clarification.

    Dew point is relevant to when a suction line sweats or not.
    It's not relevant to when a line gets below the freezing point.

    Let' take an R-22 TXV metered evaporator set for 12-F superheat.

    First load is very light & you read only 62-psig suction that's only 35-F Saturated Suction Temp (SST), add 12-F Superheat & the line temp is 47-F, usually the dew point is going to be well above that temp. That is even above beer-can cold.

    Second load is an 85-psig with a 51-SST add 12-F SH 63-SLT.
    The dew point could be below that temp & therefore NO sweating on the line; also a 63-F suction line is not going to feel beer-can cold.

    We have to take both the suction & high-side refrigerant line temps & pressures & do the math to get both Superheat & Subcooling so we know what we're doing; beer-can cold & a sweating line does not work, it's even more critically important on high SEER systems that operate at higher suction pressures & line temps, with a given heatload....
    I presume your comments are directed at your fellow techs as they're over my head. Nonetheless, they raise another question. Is there a minimum OAT to troubleshoot this or other issues?

    Thanks to everybody that replied. This is one of the best forums on any subject anywhere.

    I wish I could retain one of you experts for my HVAC needs. I looked at the contractor locator map but there is only one listing in the Kansas City area, but that contractor only has a Facebook page with no info about the company other than a phone number. He may be great, but the lack of info about the company doesn't inspire confidence. Not sure how I could search for postings on this forum by the contractor. I searched the company name, but no luck.

  3. #16
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    May 2005
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    midwest USA
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    25
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  4. #17
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    May 2005
    Location
    midwest USA
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    Had my second opinion. They put in 3 lbs of R-22. Everything else was fine. I moved in two years ago, so not sure when last service was to gauge rate of refrigerant loss. Guess we'll see next year.

  5. #18
    Join Date
    Jun 2005
    Location
    SW Wisconsin
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    4,810
    Quote Originally Posted by scouts22 View Post
    Had my second opinion. They put in 3 lbs of R-22. Everything else was fine. I moved in two years ago, so not sure when last service was to gauge rate of refrigerant loss. Guess we'll see next year.
    You may not have to wait until next year to find out...

    So, they didn't locate the leak & fix it.
    The least they could do is locate the leak; if it's a large enough leak it should be easy to find.

    Also needs to indicate whether the leak is on the high-side or low-side; low-side leaks can mean a lot of air & moisture drawn into the system.

    Refrigerant is expensive...over-time moisture in the system is also very costly...

  6. #19
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    May 2005
    Location
    midwest USA
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    25
    Quote Originally Posted by udarrell View Post
    You may not have to wait until next year to find out...

    So, they didn't locate the leak & fix it.
    The least they could do is locate the leak; if it's a large enough leak it should be easy to find.

    Also needs to indicate whether the leak is on the high-side or low-side; low-side leaks can mean a lot of air & moisture drawn into the system.

    Refrigerant is expensive...over-time moisture in the system is also very costly...
    They didn't say about hi/lo. Yes, putting in that much refrigerant is not something I would do more than once. They indicated that locating a leak is generally too difficult and did not attempt. What is involved with locating a leak? Thank you.

  7. #20
    Join Date
    Sep 2008
    Location
    Western PA
    Posts
    25,344
    Quote Originally Posted by scouts22

    They didn't say about hi/lo. Yes, putting in that much refrigerant is not something I would do more than once. They indicated that locating a leak is generally too difficult and did not attempt. What is involved with locating a leak? Thank you.
    Sounds like a lazy tech.

    My experience is that a quality leak detector and a skilled tech can find leaks fast

  8. #21
    Join Date
    Sep 2005
    Location
    Atlanta GA area
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    20,780
    Hmmm,

    When I read the first post... I was thinking low refrigerant... however there may be more issues.

    It is possible somebody stole the refrigerant (kids like to inhale it for some reason)... however with a 12 year old system it is more likely a leak. Three #'s is a serious leak, you need to get it fixed. As noted... you probably will have more issues with low refrigerant.

    If the repair issue is low cost... then maybe fixing it is a good value. If it is a major component, like the outdoor AC unit (what you are calling the compressor)... then a new system would be a wiser choice.

    Remember that a new system will probably operate at higher efficiency, and come with a parts (and maybe labor) warranty. Might consider how long you plan to be in the house as part of your decision.
    GA-HVAC-Tech

    Quality work at a fair price with excellent customer service!

    Romans Ch's 5-6-7-8

    2 Chronicles 7:14

  9. #22
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    May 2005
    Location
    midwest USA
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    25
    Talked to the tech again for more details as follows. They (tech and trainee) checked and found no leak outside the house. Most likely a high-side leak. Did not check inside as 99% of leaks inside the house are in the coil. Leak check on coil is $$$ dollars. Leak repair on coil would be $$$ dollars and on a 12 year old coil would likely induce new leaks on welds from repair work.

    If later ascertain leak is small, can put stop addative in, but leak may be too big for addative--don't know yet. System lost 3 lbs out of 6-6.5 lbs. total in system. Time frame of loss unknown. Thank you.
    Last edited by jpsmith1cm; 05-07-2012 at 05:19 PM. Reason: Removed Pricing

  10. #23
    Join Date
    May 2008
    Location
    Missouri
    Posts
    3,410
    Would NOT recommend leak sealer in your freon system. We've had HORRIBLE luck with leak sealer in that compressors failed within few weeks of adding it.

  11. #24
    Join Date
    Sep 2005
    Location
    Atlanta GA area
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    20,780
    Quote Originally Posted by scouts22 View Post
    Talked to the tech again for more details as follows. They (tech and trainee) checked and found no leak outside the house. Most likely a high-side leak. Did not check inside as 99% of leaks inside the house are in the coil. Leak check on coil is $$$ dollars. Leak repair on coil would be $$$ dollars and on a 12 year old coil would likely induce new leaks on welds from repair work.

    If later ascertain leak is small, can put stop addative in, but leak may be too big for addative--don't know yet. System lost 3 lbs out of 6-6.5 lbs. total in system. Time frame of loss unknown. Thank you.
    Quote Originally Posted by wahoo View Post
    Would NOT recommend leak sealer in your freon system. We've had HORRIBLE luck with leak sealer in that compressors failed within few weeks of adding it.
    I agree, I would NOT put anything other than refrigerant (and maybe leak check dye) in the system. Leak sealer is seriously BAD stuff for the refrigeration cycle... it will create more issues.

    Most folks I talk to this year are just biting the bullet and buying a new system... in the long run if you plan to stay in the house for a while... it would be the better value.
    Last edited by jpsmith1cm; 05-07-2012 at 05:20 PM. Reason: Removed quoted pricing
    GA-HVAC-Tech

    Quality work at a fair price with excellent customer service!

    Romans Ch's 5-6-7-8

    2 Chronicles 7:14

  12. #25
    Join Date
    Sep 2008
    Location
    Western PA
    Posts
    25,344
    Quote Originally Posted by scouts22 View Post
    Talked to the tech again for more details as follows. They (tech and trainee) checked and found no leak outside the house. Most likely a high-side leak. Did not check inside as 99% of leaks inside the house are in the coil. Leak check on coil is $$$ dollars. Leak repair on coil would be $$$ dollars and on a 12 year old coil would likely induce new leaks on welds from repair work.

    If later ascertain leak is small, can put stop addative in, but leak may be too big for addative--don't know yet. System lost 3 lbs out of 6-6.5 lbs. total in system. Time frame of loss unknown. Thank you.
    No leak sealer. Bad juju. You WILL have a bad compressor in short order if you choose that route.

  13. #26
    Join Date
    Dec 2009
    Location
    B.C.
    Posts
    26
    No * and brand bashing.
    Last edited by Stamas; 08-18-2012 at 06:22 AM.

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