Home A/C issue- clogged evapoaratr coils??

Discussion in 'The Garage' started by Lomez, Sep 13, 2019.

  1. Lomez

    Lomez Been here awhile

    Joined:
    Mar 27, 2011
    Oddometer:
    307
    Location:
    San Francisco, CA
    This is a rental home and I have and I'm stumped. AC wasn't blowing cold so I thought. It didn't relate tested it I could feel the air was actually blowing cold unfortunately was barely trickling out of the vents. Check the blower motor doesn't seem to be a problem. Check the intake air filter no problem. Even when I completely remove the filter and let it flow freely it does not improve the flow. However, when I open the access panel and allow air to Simply bypass the evaporator coils, it was like a hurricane. So I have determined that the choke point could be nothing other than the evaporator coils themselves. I sprayed coil cleaner all over them and use the scrub brush even when it's them and it did not help at all. I poured some vinegar on to them and that did not help either. They are NOT iced over that is not the problem.

    Has anyone heard of something like this? The unit is very old like 25 years. It needs to be replaced but this is a home I'm going to sell I just wanted to be cool for showings. Is it possible for evaporator coils to Simply corrode and block airflow? Anyone seen something like this?

    Wondering if I should try CLR or something. ?
    #1
  2. Yinzer Moto

    Yinzer Moto aka: trailer Rails Supporter

    Joined:
    Jun 13, 2008
    Oddometer:
    26,124
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    Use more pressure? Like compressed air to blow through the coils. A garden pump sprayer might work.
    #2
    SmittyBlackstone likes this.
  3. dtysdalx2

    dtysdalx2 Knowledge is horsepower

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    21,977
    Location:
    Moneyapolis, MN
    In reach in food coolers the acids in the tomatoes can kill evaporators. Some have a blue coating on the AL to avoid oxidation.

    Any acids in the air? 25 years old is old.

    Check the speeds of the blower too. Usually 3-4 speeds maybe you can boost it up one speed.
    #3
  4. ydarg

    ydarg Miscreant

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    Nov 11, 2015
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    If it has an "A" or "N" coil and is an upflow unit, the coil will most likely have to be physically removed to clean it if the airflow is that low. Nothing you do will effectively clean the crud that's glued to the bottom side of the coil which you can't access.

    Rental property, where the tenants before you probably ran it without a filter for who knows how long while their 4 dogs and 9 cats roamed the house because "it ain't my house".
    #4
  5. quickstang87

    quickstang87 Adventurer

    Joined:
    Feb 11, 2013
    Oddometer:
    80
    Location:
    Phoenix, AZ
    If the unit is 25 years old and you are selling the house, why don't you just put a new A/C unit on? Don't you think potential new owners will find out how old the unit is during inspections?
    #5
    Tmaximusv likes this.
  6. YesRush

    YesRush Long timer

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    Aug 17, 2014
    Oddometer:
    2,363
    Location:
    Va
    If you didn’t know the coil access panel can be removed you probably shouldn’t remove it.
    If you do,the blockage is on the side of coil you didn’t brush.
    Pictures?

    Then if you think it’s clean because it’s flowing air but isn’t totally clean you have a possibility of water damage.

    I wouldn’t put a nickel in it being 25 yrs old.
    It’s 50/50 if you can clean it.That is if you go by the two I cleaned.
    #6
  7. lnewqban

    lnewqban Ninjetter

    Joined:
    Jan 22, 2012
    Oddometer:
    945
    Location:
    Florida
    Yes, after so many years exposed to humidity, dust, acids produced by mold and fungus and caustic action of chemical cleaning the aluminum fins get corroded, become fragile and fall apart.
    Further coil cleaning should be done only after removing the coil from the handler and the cleaning agent should be washed away with slow flow of water (fragile fins).
    If that is the case of your coil, replacement of it or entire air handler would be the best way to go.
    #7
  8. Tmaximusv

    Tmaximusv Long timer

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    Location:
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    FWIW the rental I live in (I have a great LL BTW) has a 35 YO unit. After several non cooling calls this past summer, they decided to check for leaks (duh?). New handler and compressor will be going in next week. :clap

    +1 on not putting any money into an old unit. You’ll probably make back the cost in electricity charges at some point.
    #8
  9. Yinzer Moto

    Yinzer Moto aka: trailer Rails Supporter

    Joined:
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    If that coil is blocked, it should be removed or cleaned before heating season, if the air is not moving through the furnace fast enough, it will be bumping up against the high limit temp switches.
    #9
    lnewqban likes this.