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  1. #1
    Join Date
    Jul 2013
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    14

    Mold in HVAC, Part 3

    I wrote to you guys previously. I had mold in my HVAC system and had the coils, pan, drain and plenum cleaned twice but it still had a mold smell. Finally I fogged the HVAC system twice with Concrobium Mold Control until there was a thick visible fog throughout the house, and this got rid of the mold smell. But now I need to make sure that the smell doesn’t come back or maybe filter the air from the HVAC system so that at least the mold will be filtered before it’s distributed to my rooms. This is speculation on my part. Are there any reasonable ways to control or filter any mold in my system? I have heard some reports that filtering does more harm than good and can actually make mold grow or the filters can harbor mold??

    I can’t fog that often because I had to leave my house for several days because the fogging agent hurt my lungs. And I can’t use any HVAC purifier that releases ionized oxidizers (ActiveTek or RGF) into the air because this makes me sick, as does the ozone from UV lights. The humidity in my home has been consistently between 32 to 41 percent, and I live in Roseville, CA. I plan to have the coils, pan and drain cleaned every 6 months and to change the air intake filters with a Merv 8 filter every two to three months. I’m hoping that the leftover mold smell was maybe spores in my ducting that the fogging got to. Two techs have looked in the attic and every place visible and there aren’t any signs of water damage. So do you guys have any ideas for how to keep the mold out of my system or how to filter it? I had to leave my house until I can get this resolved so I would really appreciate any ideas. Thank you so much.

    Sincerely, Liz

  2. #2
    Join Date
    Jun 2003
    Location
    Madison, WI/Cape Coral, FL
    Posts
    6,437
    When your a/c operates, the supply ducts are 80-90% RH for hours. The temp is low but the %RH is high enough for mold growth. Moisture is on the cooling coil which slowly evaporates off the coil during the off cycle back to the home. These are conditions that may grow mold.
    Operating the blow in the "on" low mode during when the a/c is not cooling will thoroughly dryout the ducts and coil/pan for several hours every day. Mold spores are everywhere and can not be eliminated by filtering. Several hours of drying everyday will prevent mold growth. In your low humidity climate, the fan "on" mode should not cause +50%RH. If your indoor %RH exceeds 55%RH, supplemental dehumidification is suggested.
    Regards TB
    Bear Rules: Keep our home <50% RH summer, controls mites/mold and very comfortable.
    Provide 60-100 cfm of fresh air when occupied to purge indoor pollutants and keep window dry during cold weather. T-stat setup/setback +8 hrs. saves energy
    Use +Merv 10 air filter. -Don't forget the "Golden Rule"

  3. #3
    Join Date
    May 2004
    Location
    south louisiana
    Posts
    3,187
    did you ever open up a duct at the supply plenum & see if mold is
    in ducts &/or plenum? look inside supply boxes?

    if the ducts etc are mastic sealed...no condensation & voc's get into
    the ducts/plenum etc. fogging is a bandaid until you find the source of
    moisture causing mold.

    best of luck.

    teddy bear please check your pm's..thanks!
    The cure of the part should not be attempted without the cure of the whole. ~Plato

  4. #4
    Join Date
    Jul 2013
    Posts
    14
    Thank you Teddy and Energy Rater: I run the fan 24/7 all the time. I got mold before with the fan running but I didn't realize how often I was supposed to have the coils cleaned. So is it possible I had mold in the coils which probably hadn't been cleaned for at least two and a half years and maybe leftover mold spores in the ducts and the fan area and the fogging got it? Energy Rater, I called several companies and asked if they would open up the supply boxes and check the fan for mold, but they basically told me that I had to get a mold remediation person if I wanted that done, which I couldn't afford. This is why I fogged the ducts and systems with the Concrobium on the advice of a local guy I called from the NADCA website. If there was residual mold left from the coils, I'm hoping this will be enough and I will have the coils cleaned every six months and be more diligent about the air intake filters.

    If there's a source of moisture that the techs couldn't see, then I'm in trouble because the mold guy wanted $600 to $1000 just to come and take air samples, which wouldn't have been truly helpful. I called about five HVAC companies, and they just kept saying that mold wouldn't be any place other than the coils, pan, drain and plenum. I told them what you guys told me, but they wouldn't listen. And the mold guy said that having someone take a camera and look in the ducts could cause harm because it can rip the plastic lining. They did say that because my house is in CA and only three years old, the builder would have had to test the ducts for leakage (less than 6 percent) before selling the house so they should be good, and that it would be very costly to pull apart any ducting. So it felt like the only option was to fog. But if the mold comes back quickly then I will know I have a more serious water problem. I can’t use regular PCO purifiers that put oxidizers into the air because the oxidizers are dangerous, but I found a PCO room purifier that draws air through the unit with a fan and the oxidizers are substrate bound. The tech is used in operating rooms, hospitals and food processing, so these purifiers might be a possibility but I don’t know if they would keep up with mold squirting out of the air conditioner all the time. So I turned the HVAC fan back on 24/7 and it has been running since I fogged. Is there anything else I can do to keep the mold away? I’m desperate to be able to move back into my house and mold makes me very sick very quickly. I really appreciate your guys help. Thank you so much.

  5. #5
    Join Date
    Jun 2003
    Location
    Madison, WI/Cape Coral, FL
    Posts
    6,437
    Quote Originally Posted by LizFromCA View Post
    Thank you Teddy and Energy Rater: I run the fan 24/7 all the time. I got mold before with the fan running but I didn't realize how often I was supposed to have the coils cleaned. So is it possible I had mold in the coils which probably hadn't been cleaned for at least two and a half years and maybe leftover mold spores in the ducts and the fan area and the fogging got it? Energy Rater, I called several companies and asked if they would open up the supply boxes and check the fan for mold, but they basically told me that I had to get a mold remediation person if I wanted that done, which I couldn't afford. This is why I fogged the ducts and systems with the Concrobium on the advice of a local guy I called from the NADCA website. If there was residual mold left from the coils, I'm hoping this will be enough and I will have the coils cleaned every six months and be more diligent about the air intake filters.

    If there's a source of moisture that the techs couldn't see, then I'm in trouble because the mold guy wanted $600 to $1000 just to come and take air samples, which wouldn't have been truly helpful. I called about five HVAC companies, and they just kept saying that mold wouldn't be any place other than the coils, pan, drain and plenum. I told them what you guys told me, but they wouldn't listen. And the mold guy said that having someone take a camera and look in the ducts could cause harm because it can rip the plastic lining. They did say that because my house is in CA and only three years old, the builder would have had to test the ducts for leakage (less than 6 percent) before selling the house so they should be good, and that it would be very costly to pull apart any ducting. So it felt like the only option was to fog. But if the mold comes back quickly then I will know I have a more serious water problem. I can’t use regular PCO purifiers that put oxidizers into the air because the oxidizers are dangerous, but I found a PCO room purifier that draws air through the unit with a fan and the oxidizers are substrate bound. The tech is used in operating rooms, hospitals and food processing, so these purifiers might be a possibility but I don’t know if they would keep up with mold squirting out of the air conditioner all the time. So I turned the HVAC fan back on 24/7 and it has been running since I fogged. Is there anything else I can do to keep the mold away? I’m desperate to be able to move back into my house and mold makes me very sick very quickly. I really appreciate your guys help. Thank you so much.
    Mold needs 24 hours of continuous wet to grow. So suggest several hours of dry time everyday for coil/pan/ducts without the a/c operating and fan on. Merv 9 filters are minimum. Accumulated dirt can look like mold. Fan "on" and make sure that the a/c is not operating for more than 12 hours continuous.
    Make sure you drain pan is dry at the end of the fan "on" time. I assume that you have <50%RH in the your living space all the time.
    Regards TB
    Bear Rules: Keep our home <50% RH summer, controls mites/mold and very comfortable.
    Provide 60-100 cfm of fresh air when occupied to purge indoor pollutants and keep window dry during cold weather. T-stat setup/setback +8 hrs. saves energy
    Use +Merv 10 air filter. -Don't forget the "Golden Rule"

  6. #6
    Join Date
    Jul 2013
    Posts
    14
    It wasn't that anything looked like mold, but that I could smell the mold coming from the vents and started to have neurological symptoms. The air conditioner doesn't run continuously. It comes on several times per hour -- or is that considered continuous? It usually gets a break from about midnight to 10 am and sometimes longer. Is this OK? The humidity in my living room has been between 32 to 42 percent. I plan to get a second humidity monitor for my bedroom. I do currently have Merv 9 filters that I just put it. And the fan is running 24/7. Would fresh air ventilation help? Don't know if I could afford it, and all the HVAC people here don't seem to have a clue about fresh air ventilation (have never installed it)? Do you think room purifiers would help? Thanks.

  7. #7
    Join Date
    Jun 2003
    Location
    Madison, WI/Cape Coral, FL
    Posts
    6,437
    Quote Originally Posted by LizFromCA View Post
    It wasn't that anything looked like mold, but that I could smell the mold coming from the vents and started to have neurological symptoms. The air conditioner doesn't run continuously. It comes on several times per hour -- or is that considered continuous? It usually gets a break from about midnight to 10 am and sometimes longer. Is this OK? The humidity in my living room has been between 32 to 42 percent. I plan to get a second humidity monitor for my bedroom. I do currently have Merv 9 filters that I just put it. And the fan is running 24/7. Would fresh air ventilation help? Don't know if I could afford it, and all the HVAC people here don't seem to have a clue about fresh air ventilation (have never installed it)? Do you think room purifiers would help? Thanks.
    Run for a couple weeks and see what happens.
    Most homes have enough air leaks during moderate winds to be ok. During calm weather air change declines.
    Complicated to test for fresh air changes.
    Keep us posted on the results of the fan on and monitoring the %RH.
    Regards TB
    Bear Rules: Keep our home <50% RH summer, controls mites/mold and very comfortable.
    Provide 60-100 cfm of fresh air when occupied to purge indoor pollutants and keep window dry during cold weather. T-stat setup/setback +8 hrs. saves energy
    Use +Merv 10 air filter. -Don't forget the "Golden Rule"

  8. #8
    Join Date
    Jul 2013
    Posts
    14
    Yes, I'm praying the mold doesn't come back. I think the house is pretty tight. Since I don't have a ventilator, I've been using four fans (two pulling fresh air in and two pulling it out across the house). Is this okay to do? Are there any downsides? I check the fresh air quality outside before doing so. My version of cheap fresh air ventilation. Thanks for your help.

  9. #9
    Join Date
    Oct 2008
    Posts
    32
    Pulling in fresh air & blowing out the chilled AC air is why you have a constant mold & AC mold problem & high humidity problem.

  10. #10
    Join Date
    Jul 2010
    Location
    nebraska
    Posts
    1,629
    What do you guys think about removing the internal insulation from the air handler then wrapping it from the outside? Guessing those spores are trapped in the insulation.

  11. #11
    Join Date
    May 2004
    Location
    south louisiana
    Posts
    3,187
    shoot marty...she can't even get someone to take off a flex
    duct & look inside the plenum...
    without signing on for a full mold remediation.

    where it is...what caused it ...(where the moisture
    come from & what the food source is) is still unknown.

    as far as removing internal insulation...the glue that
    holds the insulation in place will hold fiberglass particles
    so that will enter the air stream unless encapsulated.
    if she can find someone to do that...then they could
    wrap it externally ....and take a look inside the supply plenum.

    but the orginal source of moisture issue would have to be solved..
    or it will just come back.

    there are lots of mold issues here where temps & RH is so high.
    remediation companies love these houses. but they spend
    all the homeowner's money on remediation...without solving
    the issues that caused mold to begin with. so 15 grand later
    & a year down the road...it comes back.

    I spend a good bit of time convincing the homeowner that
    the mold type doesn't matter...so samples are just for ID purposes.
    fixing the cause of moisture...that is where it starts & stops.

    better to spend the $$ on fixing the problem than knowing the
    name of the mold that you are growing.
    and btw...I'm certified to do mold testing. and do very little
    of it. mostly for lawyers & court cases.

    for homeowners...I just fix the moisture source & remediate
    the food source.

    it is sad that the op can't get someone to just open
    things up & take a look.
    The cure of the part should not be attempted without the cure of the whole. ~Plato

  12. #12
    Join Date
    Jul 2013
    Posts
    14
    I only started using the fans after I fogged and got rid of the mold -- to bring in fresh air to dilute the leftover Concrobium fogging agent -- and doing it at night to pull in the cooler outdoor air. And the humidity has remained between 32 and 41 percent indoors. Right now, the HVAC system no longer smells like mold. I am hoping that the mold smell was residual spores leftover in the ducting after the technician cleaned the coils, pan, drain and plenum twice. Fogging twice got rid of the leftover mold smell. If it comes back quickly, then I can assume that I do actually have a moisture problem. Before I fogged, I had called at least five HVAC companies and none were willing to do anything other than clean the coils, drain, pan and plenum, and a few said they could put a camera in the ducts and look and then clean them but it would be expensive. And the mold remediation specialist said that the camera and cleaning could tear the plastic in the ducts and actually make the situation worse. I agree with Energy Rater that knowing the type of mold isn't particulary useful. If it causes symptoms, it's definitely a type of mold that produces mycotoxins and it has to be eradicated. So right now, it doesn't smell like mold but the house still has too much Concrobium so that it's hard to breathe. I am borrowing a PCO purifying unit to clean out the Concrobium in the house when I'm not there because it's very bad to breathe in the radical oxidizers. I'm just really hoping that the mold doesn't come back because I haven't been able to live in my house for ten days -- first the mold made me sick, then it was the Concrobium. I'm open to any and all suggestions. Thank you.

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