1/2 vinegar 1/2 hot water works for me all these years. Do it twice a year.

Need watch see if they gain access to A coil and check pan put tablets in. IMO what paying service for. Some unit designs nearly impossible to get front cover off gain access to A coil drain pan. My new carrier extremely hard to get access to A coil and drain pan due to lines, vent, and aluminum taped up like fort knoxk. My old Trane was easy access. I should have got Trane. But maybe it will be next guy problem?

I just installed new unit last week -- they advised to only use warm water. You may want to call the manufacturer of your unit.

I'm not sure who installed your new unit, but with my new Carrier unit installed last week by Sunshine, It's very easy to open the cover to access the coil. And I think that's important. Also, your unit shouldn't need to be taped up like fort Knox. The one thing I noticed between my old Carrier system and my new one is there are gaskets on the all the door and filter panels and there are no air leaks. Good job Carrier. The only places you should need tape is where it connects to the upper and lower plenum. This is why I always say when making a decision on who go with, price is important but beyond that, the install is extreemly important and will determine how long your unit lasts.

I know this is a little off topic but when you put in a new system you also need to know:
1) Are they using nitrogen when brazing?
2) How much vacuum are they pulling before releasing the refrigerant?
3) Are they giving you a new line set?
4) Are they insulating the new line set all the way under your water heater to the outside wall?
5) Are they insulating the condensate drain?
6) Are they providing the proper size replacement unit? Did they do a new heat load calculation?

What do you think the Vinegar, Acetic acid, is doing to help clear the line? I think you would basically get the same results by pouring Top Job or Mr. Clean down the drain and flushing it out.

The reason why it's working for you is you are maintaining the drain so no matter what you use, your drain will remain clear.

Completely different unit than you’re. I just flush my drain out the 55 Psi water pressure. Takes about 4 mins.

Once a year I open up the unit to get to the condensor and if I see any small mold spots inside the area or the condensor coils I use a mild bleach solution to spray the coils and sides, let that sit for 15-20 minutes to kill the mold, then spray with fresh tap water (don't use too much). I do this after I turn off the A/C at the breaker box. Close the unit back up and wait 1 hr before turning the A/c back on. I'll use warm water to flush the condensate drain all the way out the side yard. If I see white gunk in what comes out the condensate drain in the side yard I know that there is stuff growing in the condensate line that will not be killed by warm or hot water. Suck out the line with a shop vac, then fill condensate pipe with mild bleach water (2 quarts) , let it sit for 1/2 hour to kill what ever is growing, suck it out again and flush with clean water. PVC pipe does not like bleach so don't leave in the pipe too long. If one is very concerned about damaging one's PVC drain pipe, then I suggest using "bromine" which is just as effective (obtained from just about any pool store.

Just remember most of our condensate lines are buried in the concrete slab so be careful not to damage it with chemicals as you started.

In CYVs There 4 inch pvc pipe usually where copper lines and pvc drain ran all way up to unit under garage floor slab. They replaced all my line by running new lines through underground cavity by tying rope on to old lines and using the it to pull new lines under and up in side floor box. If they couldn’t do that then out side wall up through attic was other option.

My common sense tells me that both vinegar and bleach are corrosives and that the PVC pipe that runs from one end of the house to the other is most likely more than one pipe with a connector with some type of glue. If a corrosive is used, there could eventually be problems with the connector, then you will have an even bigger problem. I only use hot water for that reason. But I did read the response about the Dawn, so I may start doing that. :bowdown:

I guess this is why Carrier says do not pour Vinegar down your condensate drain.
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Corrosion is one of the leading causes of AC cooling coil leaks. The coil’s material, usually copper or aluminum, can react with chemicals in the air. These reactions, especially involving formic acid or acetic acid, eat away at the metal, creating small pinholes over time. Common sources of these chemicals include household cleaning agents, adhesives, and paints.
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Is anyone still using any exotic chemicales to flush their A/C condensate draines?

I have a neighbor that swears using TopJob, Ammonia and a little Bleach has kept his drain clean for over 20 years! But never mix Ammonia and Bleach since it produces toxic fumes.

So we shouldn’t cook with vinegar or clean with bleach in our house? After all, unlike the water in the drain lines the air in your house will be collected and pushed directly through the coils. If it is strong enough to harm fabrics and burn your skin and eyes then just imagine what it must be doing to the soft aluminum and copper of the coils.

NO to Ammonia, and bleach !
 

NEVER mix Ammonia and BLEACH....It makes Chloramine gas....which can KILL you.

You have a good point LOL but it's the concentration that causes the problem. So having the fumes in the condensate line are probably stronger than what would be sucked into the return from your room?