Mold on Airhandler insulation
srivenkat
| Posted in Mechanicals on
When I open the Electric furnace / Air Handler, I see blackish stuff on the fiberglass insualtion, which I presume is mold. I am planning to take all that insulation out. The Air handler is in a conditioned basement. Should I be replacing the insulation with something else? If not, is there a glue or paint or something like that that I should apply on top of the last remaining fiberglass elements glued to the panels, so they don’t come off and enter the duct system? Thanks in advance for any advice.
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Is there a lot of moisture in the air handler? If not, you may be seeing dirt that has accumulated in the fiberglass insulation.
It needs to be airtight, otherwise water will condense on the warm side of the insulation. See https://www.storeitcold.com/insulation-information/
The AC coil is also in the Air Handler so there's moisture that condenses when AC runs. I have run my finger on the fiberglass and I picked up what's as black as mold. I am very much inclined to just take the insulation out and I am trying to understand how I can make sure the remaining fiberglass hairs don't break off and enter the ducts. I am not concerned with any condensation issues cropping up since the unit is in conditioned space and I have never seen any condensation on the take-off and such that are NOT currently insulated.
I understand I would loose the sound-dampening that the fiber-glass insulation provides. I am fine with increased sound from the unit.
Thanks in advance for any suggestions on how to make sure the remaining fiber-glass hairs can be controlled.
CLARIFICATION: The condensation that I was referring to with the AC coil is only on the AC coil, no condensation I can see on any other surface. I believe the dust that made it past the filter accumulated on the fiberglass insulation, causing mold to develop because of high humidity in that area after the AC stops running.
Venkat. The insulation in air handler in my previous home became covered with mold. It turned out that the system have a refrigerant leak, and the leak meant the system was running almost continuously and producing a lot of condensate. Enough of that moisture was transported to the air handler to saturate the fiberglass insulation. I mention this experience just in case you are having a similar issue.
We had a failure of the outdoor unit some years ago, and possibly that contributed to the issue. Did you replace the insulation or replace the unit itself?
I ended up replacing the air handler.
Venkat,
First of all, you haven't clearly described where the insulation is located. You are implying that the fiberglass is in contact with the air flowing through your furnace, and that's unusual. Many air handlers have insulation, but the insulation isn't anywhere near the interior of the supply plenum or the return plenum (where the air is actually flowing).
One place where fiberglass fibers are near the air flow is at the filter, of course. But that is deliberate. Filters are supposed to be in contact with the air flow.
A better description of the location of the insulation (or a photo) might help.
In general, mold grows in damp locations. Dampness is often a sign of condensation. Condensation occurs when humid air contacts cold surfaces.
Vinkat,
To clarify, my first air handler enclosure was made out of duct board with facing only on the exterior side. The replacement enclosure was made out of metal with the insulation with exterior insulation.
Here are some photos, Martin. Thanks.
2 more photos.
2 more photos.
Venkat,
I'm stumped. I don't have a good theory to explain what is going on.
If this were mold, I think that you would see other evidence of moisture problems -- rust, for example. Is it possible it is just dirt or smoke residue?
Martin, I am planning to send a sample to a mold lab. Is it possible that dust that may have made it past the air filter and thru the AC coil may have become planted on the fiberglass insulation causing mold in the presence of the moist AC coil, especially once the AC stops and the remaining moisture in the pan makes that area humid?
Regardless, considering the liners appear the way they do, what would be good replacements for them? If I tear them off, there will still be some fibers glued to the panels. Should I cover the remaining fibers up with another liner? I am not thinking removing the liner will cause any condensation issues since the air handler is in conditioned space? Thanks in advance.
Is that a waterline at the bottom of the evaporator coil assembly? If water is backing up in the drain pan and touching the bottom of the insulation, moisture could be wicking up into the insulation and creating conditions that support mold growth. Drain lines sometimes become clogged with debris and biofilm, so you might want to check your line to make sure it is working properly.
Venkat,
As a first step -- an evidence-gathering experiment -- take one of the panels outside and spray it carefully with a garden hose. See how easy it is to wash this stuff off.
After Experiment #1, spray the fiberglass with a liquid spray cleaner like Fantastic. Wait a minute or two, and rinse gently with a garden hose. Report back with your findings.
Martin, I will try what you suggested and report back.
Steve, yes, there's a waterline at the base of the evaporator assembly and yes, about 3 times, the line got clogged up, resulting in water on the basement floor. Each time that happened, I would blow thru the pipe in reverse and that would clear the clog.
There has been considerable back and forth on this topic with Martin. I believe that the original poster may not be aware of what he is looking at. Many, if not all of the fiberglass duct liner products manufactured these days have a manufacturer applied black non-woven fabric that is applied to the airstream side of the duct liner or board. It is evident in his pictures that he is looking at such a product as the shots of the edges clearly shows a defined line between the black lined inside surface vs the yellow edges. Some manufacturers (depending on the specific product) also apply a coating to the edges of the product. These are designed and applied to help minimize the amount of fibers entering the airstream.
Yes, these products can become dirty over the years, but my guess is that he is looking at a black faced product and not one that is infused with mold.
Chri,
You may have solved the mystery!
.
Hi Venkat and Others, Did you replace the Fiberglass insulation by any chance any time ? My insulation is looking bad and want to replace it. It's Lennox system.