Basis on the information you provided. We now know the evaporator coil and the central air conditioner unit is not the source of the fish smells.
Is it possible the animal could have died in the attic. And lying on the mudroom cellar. You only have the smell when the central air conditioner is on. The reason I said that is cold air sink and hot air rise. It didn't smell when the heat was on, but why cold air. So that have to be it.
Here a idea.
Is there a way for you guys to spray a perfume above the mudroom cellar in the attic and then turn the central air conditioner on. I want to see if it still produce the fish smells or the perfume.
Your attic is hot, right? I don't know the reaction between hot air and perfume, so don't stay there long.
May 27, 2010 Rating
Still trying to figure out Fish Smell by: Long Island, NY
Hi Shawn,
Thank you for your suggestions. Here's what we did today to try to figure out the smell in the mudroom when the a/c is turned on.
We taped up all the a/c vents in the den and sealed the door from the den to the mudroom with a plastic drop cloth and tape. We turned the fan on for quite awhile and no smell came into the den. And I don't think the mudroom smelled either, although there was some odor lingering from yesterday (the mudroom has no vents but a trap door to the attic where the a/c unit sits.) We tried our best to seal this trap door too, but I don't think it was air tight. We then turned on the a/c, no smell in the den, but I think the mudroom became smellier. We took the tape off the vents in the den and no smell came in while the a/c was on (the den door to the mudroom was still sealed).
So that's where it stands now. Smell is definitely not coming out of the vents/ducts to the den. Definitely starting in the mudroom where there are no a/c vents, but only starts to smell when the a/c is on.
We are at a loss. Only thing we can still think of is that an animal died in a mudroom wall. But why would it only smell when the a/c comes on? We had a mouse die in our bathroom over the winter and it smelled terribly bad all the time until we figured out what caused it, ripped out the vanity and found the dead mouse, no m ore smell now (the dead mouse made a sewer smell, not like this fishy smell).
Considering ripping out sheetrock in mudroom, but hoping someone has a better idea before we go through all that.
May 26, 2010 Rating
Fish Smell From Central Ac Units by: Shawn
This is interesting and I read it 7 time. I was thinking the same thing. I thought a animal could have die in the duct works, since that is not the case. Here is my question:
Does it has the smell when you initially turn the central air conditioner on and it die out or the fish smell continence whenever the central ac is On?
What is your environment like? Is it humidity, rain a lot?
Where is the return vent near? Is there 1 or 2 returns vent?
Does the kitchen have it owns supply air vent?
How many central air conditioner do you have? 1 or 2..
On top of your mudroom and den is central air conditioner unit, right? Here what I need you to do.
1. Turn the central air conditioner unit to OFF position and wait for 5 minutes. And then turn the fan from Auto to On. ( The central ac is off, right?)
2. Does it smells?
3. If it does smell. Turn the Fan back to Auto and wait for the smell to dissipate, so you can tell the different.
4. Next block the airflow from the two vent in the den (air tight if possible).
5. After you block the two vent. Turn the fan back to On Position and where is the stronger smell coming from? Which room? Is that room near the central air conditioner units Or far from it.
Here is piece of information. All the room near the central air conditioner unit got the fish smell and all the room far away form the central does not have the smell.
