Central Air conditioning SMELLS?
We had a new coil put in our central air last year. Before that, the smell from the AC became horrible, and apparently we had bacteria accumulating on the coil inside. It was so bad, even cleaning the coil didn’t work. So they replaced it. The air was fresh and clean. That was just last summer.
Well, today we are having a very warm day in the mid 70’s. We turned the air on, and it smells horrible AGAIN. This happened too on warm days in the fall. I told the technician, and he is trying to tell me my ducts need cleaned. BUT, the heat doesn’t smell at all, and we had the ducts cleaned a few years ago. They weren’t that bad, apparently, but they did find mold.
I have asthma, and can’t cough and sputter every time the AC is on this summer. Now we have to pay again for him to get the coil out and inspect it, I’m assuming. I don’t think this is fair – we just paid over a thousand dollars for the coil, which he said should last 8 plus years.
What could this be? Bacteria again? Will a UV light solve the problem, and, will we need yet another new coil?
What should he be checking when he comes? He seems to act like he has no clue. What am I suppose to do? Again, with asthma this is a really bad problem.
Thank you!
Lets address the smell first. You had a bad odor problem in the past. You obviously had a badly blocked evaporator coil in the unit and it was replaced. The source of the smell was and is mold and slime that can accumulate in the condensate formed when air is cooled by air conditioning. As the warm moist air travels across the evaporator coil, heat is being sucked out of the air and the moisture in the air will condense into liquid water like it does on the outside of a cold can of beer. That condensate runs down the fins of the evaporator and collect into a drain pan. A drain line connects to the outlet of that pan and carries that condensate away. It may be piped to the waste water system of your home, it may be gathered into a small box and pumped away outdoors, regardless it has to have a place to go and it has to be free of obstruction. If not taken care of mold and slime can and will begin to grow in the drain pan or the drain line. The mold that was growing when you had the problem first were obviously there for an extended period of time and had a great opportunity to migrate through the ductwork. It may be time to consider having the ducts cleaned. Since the evaporator coil was replaced once already, and you are now needing to get back to that coil again it may be wise to have an access built in for future maintenance considerations. Your brand new evaporator coil has had a year to operate and provide another location for the mold spores to grow again. Evaporator coil can be cleaned on a regular basis and perform wonderfully for many years. Evaporator coil cleaner and microbiocides are usually applied directly to the coil by sprayer, such as a bug sprayer. It is self rinsing and will wash off as additonal condensate is formed. It usually has a pleasant odor to it. The cleaner solution is perfectly safe draining away through the condensate lines. Condensate has to be able to flow freely away from the machine. If the condensate drain connection is on the suction side of the air flow, it is necessary to have the drain lined P trapped. Without a P trap, air will be sucked in through the drain connection and allow water to build up in the tray. That water will spill over the edges of the drain pan and create problems. With the P trap, no air is sucked back in through the drain connection and the condensate flows away freely. If the drain connection is on the outlet side of the air flow and it is positively pressure by the blown air, then the water will flow away freely. Occasionally pouring a little bit of bleach through the drain system will help keep down the mold and slime from accumulating anywhere. You may also want to have a look at the surrounding areas where any of the moisture could have been leaking. Wall board will hold a lot of moisture in it and is a perfect host for the mold spores.