Repair Rusted Attic AC Condensate Pan??

Discussion in 'HVAC Heating & Cooling' started by robhouston, May 28, 2007.

  1. robhouston

    robhouston New Member

    Messages:
    12
    I've got a central AC unit in my attic, and the main coil condensate pan is rusted through, to the point where the condensate is leaking into the "backup" pan. Last year, I attempted to fix the pan with an epoxy material, which worked for a short while, but now the pan is leaking again, and the drain is still clear.

    My guess is the way to properly fix the pan is to have a tech come out and perhaps replace the coil. My problem with this is that the AC is already 14 years old, so I'm thinking that it doesn't have too much life left, and it's working fine, except for the condensate leak. So, I hate to spend that much money on an older unit.

    I've been thinking that as an alternative, I can fashion a pan to install between the coil cabinet (horizontal unit installation about a foot off the floor of the attic) and the backup pan, and pipe this "new" pan into the primary condensate drain. So, I'd effectively catch the leaking condensate before it comes in contact with the backup pan/drain.

    Does this approach make sense, or am I better off spending quite a bit of money to have this properly fixed? Again, my main concern is that this is an older unit, and I'm thinking I'm better off saving my money for eventual replacement. Am I missing something with this thinking?

    Thanks, in advance, for your advice!

    Regards,

    Rob
  2. Phil H2

    Phil H2 New Member

    Messages:
    125
    Location:
    Tujunga, CA
    A new AC unit could lower your electricity bill. Also, see if your utility company offers any rebates for installing a new energy efficient unit. See if any federal tax credits are worthwhile http://www.energystar.gov/index.cfm?fuseaction=rebate.rebate_locator

    An HVAC contractor friend sometimes replaces the entire unit because the pan leaks. He hates to do it, but sometimes it is the only thing that makes economic sense. You might try calling a couple HVAC companies to see if they can just replace the pan (or entire coil assy) and if it is worthwhile.

    I don't know if it is significant, but the condensate drain typically has a trap to prevent air leaking through the drain. Your auxillary pan won't prevent air from leaking through the hole.
    Last edited: May 28, 2007
  3. robhouston

    robhouston New Member

    Messages:
    12
    Phil:

    Thanks for the fast response!

    Yes, I know I'll have to eventually replace the AC unit, but then there is the question of the attached furnace. What I'm trying to avoid is dumping a lot of money into this 14-year old system, only to replace all of it within the next 3 or 4 years. So, I'm looking for alternatives to increase the life of the system, for now.

    As far as the trap, you're right---my solution wouldn't include one, but there is also not one on the system now, so cold air leaks through the drain.

    I'll probably talk to a contractor to get a better idea about what I'm facing and when I need to face it.

    Thanks again,

    Rob
  4. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Messages:
    21,765
    Location:
    New England
    Depending on how far gone the metal is, there are some sealants that could be applied that might work. One I've worked with is called Pro-seal. I'm not sure you can easily buy it, as it is a professional use product, but I think it would work. The stuff is used in military systems to seal penetrations, and is spec'ed to seal gas tanks...it is tough, stays rubbery, and is impervious to most chemicals (they use it because you can decontaminate it after a chemical or biological attach!). It smells nasty, sticks to nearly anything, and really works. It stops smelling after it cures. The surface needs to be clean and dry before you install it. It needs to be mixed well, like any epoxy setting system to work properly.
  5. robhouston

    robhouston New Member

    Messages:
    12
    Jim:

    Thanks-----I used an epoxy product last year made by Marishawn. I mixed the two parts together, then poured it into the pan, then moved the pan around to spread the epoxy. It covered well along the edges of the pan and stopped the leak for a while, but once I restarted the system this year, a small leak appeared again. I'm thinking that the pan is so badly gone that the epoxy route won't work again.

    Thanks again for the suggestion,

    Rob
  6. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Messages:
    21,765
    Location:
    New England
    This stuff is more like a paste...it does not flow, you need to spread it...it remains flexible.
  7. jbljohn

    jbljohn New Member

    Messages:
    1
    Idea

    I have the exact same issue and was thinking of laying a heavy flexible liner in the pan and caulking around the drain line. Thoughts anyone?
  8. jimbo

    jimbo Plumber

    Messages:
    8,997
    Location:
    San Diego
    Keep in mind that you outdoor condensor, at 14 years, may be on borrowed time, although they can last 20 years. But when the time does come, it will be mandatory to replace the entire indoor cased coil unit ( not just the coil but the whole thing) because a 13 seer coil to match the mandatory 13 seet outdoor unit, will be larger. It will not be mandatory to replace the gas furnace.

    Whenever you decide to do this, you will realize a significant energy saving with the new equipment, which helps to offset the cost. Even a new furnace, which are not terribly expensive, can be had in a much higher efficiency than you now have.

    Until then, if you can cobble together a fix for your leak, I don't see any downside to that, as long as you keep an eye on it.
  9. robhouston

    robhouston New Member

    Messages:
    12
    Jimbo:

    Thanks for the response! You'll notice that my original post was from late May of this year. Since then, I indeed had the entire coil replaced with a 13 CEER unit, which as you point out, is a bit bigger. I'm continuing to use the outdoor unit, but I realize that it is on borrowed time, so when it comes time to replace it, I'll already have the appropriate coil.

    Regards,

    Rob
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