We had a new evaporator coil installed in June and we are getting a chemical smell. AC guy has checked all connections, outside unit, inside, checked the coils for leaks and finds nothing, yet whether running or not we are smelling a chemical or strong plastic smell. We used to smell it only when the unit came on, now we smell it even when it is off and mostly when we are near where the coils are. It seems to be getting worse instead of better. What can this be?
At the moment we have turned it off and are relying on a couple of window units to keep us cool because the smell is that bad.

Call the manufacturer and discuss. They may be able to help more. There is nothing mechanical or electrical in the evaporator. I'd check the air handler motor. Was that replaced too?

No, all that was replaced was the evaporator coil and the outside unit. I don't know who is the manufacturer of the coil. The smell definitely started when the coils were replaced as they wee replaced several weeks after the outside unit was. We first replaced the outside unit, then the inside coils had a leak and were 17 years old so we replaced them, the odor started immediately after replacing the coils and has continued and gotten worse.

Could it be the oil from the freon?
Possibly do they spray the coils and it is something on the coils from manufacturer and if so how do we get rid of that smell.

The oil for the Refrigerant is inside the coil, not outside. If the system is maintaining pressure, it is not leaking. The coils are cold, not hot so I don't think it is something evaporating. Is this a heat pump or a split system?

Slit system. The odor I believe is definitely from the coils, not sure if it's a "new coil smell" or what it is, but it isn't getting any better. The ac guy has checked and rechecked and no leaks are detected. He even took the coils out and checked them thoroughly. I call it a chemical smell, my daughter says it smells like plastic, it's a weird smell. My husband opened the door to the inside unit and said it was strong in there and made his eyes burn. This is so frustrating, we have been dealing with this for 3 months.

I have never heard of a new coil smell, and doubt seriously if it has anything to do with the coils, but I would sure get someone to check the wiring on my system, including the fans and blowers, because something burning/overheating is what I think you have. I lean to electrical component problem. I am surprised the HVAC guy couldn't find it. Didn't he smell what everyone else did?

Please let us know what you find.

It is not a burning or overheating smell and yes the AC guy checked the wiring etc, it is definitely a chemical smell.

You could probably benefit from a second opinion to put fresh eyes on your problem. If your refrigerant is good then what's left? That's how I would approach this challenge once the first guy could not find the issue, or a solution.

We know the odor started when the new coils were put in, the tech even removed them and checked them over really well. The odor is present even when the unit is off and I am pretty sure it is nothing more than the coils. I have done a ton of research and found other places where people have had this issue and were told that new coils have a coating sprayed on them and this could cause odors. I am now thinking this is probably the issue here. Not sure how to eliminate it other than to possibly clean the coils and run the fan for a long time.

I understand your dilemma. Where did you get these coils from and who is the manufacturer? Were they precoated from the factory? The fact that you removed them, and examined them, but found nothing was what leads me away from them being the cause of this "chemical" smell. Can you shed more light on this?

The AC guy got them from a company that sells AC parts, I don't know the manufacturer. We could not purchase them ourselves it is required that only a licensed AC person can purchase and pick up any product that freon is used in. I would need to contact him to see what manufacturer it was or I can possibly contact the company he got them from and ask, but being a holiday weekend I'll have to wait till Tuesday.
I call it a chemical smell, but it may be no more than a "new car smell" from the materials used in the coils. I just know the strongest odor is right where the coils are installed and the vents nearest the coils when it is running are the ones that put out the most smell. Even when not running we smell it near the coils only.

We could not purchase them ourselves it is required that only a licensed AC person can purchase and pick up any product that Freon is used in
I know this is a bit beside the point but your statement is not quite true . I can buy a condenser and evap coil, they are even on eBay, install and wire it up BUT, I cannot charge the unit with a refrigerant unless I have an HVAC license. I have done this a few times. Freon is not a generic name it is a DuPont trademark so today they are called refrigerants. Automobile AC units are sold in parts stores, Amazon, eBay and others and they do have "Freon".

I do a lot of home inspection work and have never run into your circumstance. Over heated breakers, transformers and wiring odors but not coils.



My husband opened the door to the inside unit and said it was strong in there and made his eyes burn.

Door to the air handler or evaporator coil compartment?

Well from the place we got this coil they required an AC licensed person to pick it up and pay for it. Maybe different laws for different states I don't know.

The unit is inside a vented closet like enclosure, the door is on this closet. It is not a burning odor, a hot odor or anything like a wiring odor, I know those odors and this is more of a chlorine odor in a swimming pool, a chemical like odor.

Posting a photo might be a big help in diagnosing the problem. At least we'd all be on the same page.
WallyH

A photo of what?

A photo of the evaporator coil and its enclosure, the air handler, etc. Anything that passes air and you can get to with a camera. Maybe somebody will see something that will be a clue.
WallyH

Maybe reading this older thread can help you solve this mytery smell.

https://www.askmehelpdesk.com/heating-air-conditioning/new-c-has-strong-odor-442029.html

Have you checked your condensate drain? Did you remove and clean this new evaporator after detecting this smell? If so with what?

Are there any other articles in this closet?

https://advanced-air.com/help-guides/troubleshooting/why-does-my-air-conditioner-smell-like-chemicals

It would seem this is a more common problem than I thought.

Thank you for the links, I will read through that.

Yes, drain has been checked.

We do notice the smell at the blower fan which is above the evap coils. I have read on another site that a defective or malfunctioning blower motor can heat the insulation in the blower unit and it causes a bleach like smell. We are currently looking into that.

No the closet is not large enough for anything other than the unit that is in it, it is specifically made to house the AC/heating unit and that is all. The blower fan is at the top, the heating (propane heat) area is in between and the evap coils sit on the bottom. Smell has nothing to do with the heating area, I don't think the pilot on the heat is even lit, it is off.

AHA, the plot thickens. Don't see many downdraft models in the Atlanta Area. Please explain how the airflow runs. Does it go into a crawl space plenum or is all the airflow ducted? Could possibly be picking up something from there. The air handler section is under negative pressure. Where are the cold air returns?

Well checked the whole fan system and motor, not the cause.

The duct work and vents are in the floor, our house is off the ground not on a slab. It's not the duct work since the problem wasn't present till right after cols were installed and the duct work was replaced a year or so ago so it is all fairly new. Never had any odor or issue till the new coils were installed, the odor showed up immediately after the coil install.