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airheatman, HVAC Technician
Category: HVAC
Satisfied Customers: 8326
Experience:  Furnace, A/C and heat pump specialist.
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Attic AC issue

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found leak in my room ceiling, went up straight to attic, and found issues with the AC unit, see attached pics. The condensation water does go out when AC runs, as I can see from outside. But there is so much water in the pan under the AC cabin, and the attic floor got wet, that's why I saw wet ceiling in my room. Can someone give help?

Hello.Sorry you are having problems. My name is XXXXX XXXXX I will do my best to help.Please wait to leave rating until we are finished.It sounds as though the main drain is stoped up. There should be no water in that bottom sheet metal pan.Installer should have put a clean out tee in the drain line from the coil itself(The one with the trap)At this point you are going to need to cut the pvc pipe, blow out the drain and then re connect with a new coupling.Have some towels or a bowel ready when you cut the drain as all backed up water will run out.
You can use an air tank to blow out the drain. I'm sure no supply house is open today, but hvac supply houses carry a co2 kit for blowing out the drain. Here is a link to the kit mentioned.
Customer: replied 4 years ago.

I took a look at the hole on the wall of the pan where the pvc pipe connects to the pan, there seems to some space between the bottom of the pan and the lower edge of the hole, in this case there will be always water in the pan. Unless the hole touches down to the pan bottom, the water will be there.


What I meant is even if you cut the pipe and get a new one, there will be the water in the pan. Should there be any water in the pan at all? If not, then the issue is to find out how water gets in there.


I can feel water drop dripping near the connection between the top pvc and the AC unit (see the attached pic, marked with red color).

Customer: replied 4 years ago.

are you still there? please release to others if you are not able to answer.

Customer: replied 4 years ago.

Hello, you are holding my question, please release to others, or you may get a negative rating!

Sorry got called away. Just got back.Thouight question had been answered as first question made no mention of the other issues.Can you attach a picture of the issue about yhis space? Your main drain should connect directly to the coil fitting.

If I am understanding what you mean , is that the drain hole in the sheet metal pan is up a bit from the bottom, that is normal. Thee should NEVER NEVER be water in that sheet matal pan. The reason there is water in that pan is because there is a blockage in the main drain, probably the trap is filled with the slime produced by natural evaporation and condensation.from rust in metal pan it appears this may have been an issue for some time. You are going to have to cut the main drain and blow it out as described eralier. At this point, go ahead and blow out the line from the metal pan also.
I see you have left again.I am going to step away from computer also. I will open to other experts while I am gone. Let us know if you have any more questions .
Russ here.. Your drain is stopped up. Take a shop vac and vacuum line from outside. Then go and vacuum out water in pan. The pan does need repair if there is gap between pipe and pan outlet. Dry pan and take silicon around the outlet. I will be here if you need me. Russ

As mentioned earlier, the drain fitting being up a little bit from the bottom is normal.Usually about 1/2" up is where the fitting is located.If this is the case, there is nothing wrong with your drain pan.The reason there is water getting in that pan to begin with is that your main drain is stopped up most likely. When the main drain stops up, the water overflows from the main coil drain pan attached to the coil and drips down through the unit into this pan. That is why it is called an emergency pan.You simply need to cut the drain, blow it out and reconnect with a coupling as described.Actually rather than a coupling, I would install a TEE "Float saftey switch in the main drain line. That way when drain stops up , the float switch will cut the unit off and prevent it from making any more water(before it drips into pan or on ceiling)You can buy such a float safety switch TEE at any HVAC supply house for less than 20 bucks. Thanks again. Let me know if you need further assistance.

Customer: replied 4 years ago.

By main drain, you mean the white pvc on the top? I took more observation, the water in the pan is a result of overflow/drip from the hole (looks like a soket) next to the top pvc pipe (main drain in your words). I agree mostly likely the drain has been blocked. So I need to work on this. The think is it is up in the attic, not straight forward. I'll get a pic later.

The main drain is the upper one. The one with the trap in it. Most likely the blockage is in that trap. I saw where another expert mentioned trying to vauum it out, but with 41 years in the business, I have seen very few times when a shop vac was strong enough to get the clog out.You might try that first as of course it would be easiest. I really suggest cutting the line, blowing it out and installing a float swicth TEE as mentioned earlier to prevent getting water on ceiling in future.

Customer: replied 4 years ago.

Where do you think is the point on the pipe to cut in? I can see the thread on the connector between the drain pipe and the unit cabin, is it better if I just use a wrench to take it off from the area I marked in red in my previous picture, in stead of doing cutting? Would it be possible that some blockage happens inside, should I open up the side to look at things inside to make sure there is nothing wrong inside? How do you know the blockage is in the pvc pipe, not inside? I don't want to cut and then find the issue is not in the pipe.

I just don't know where exactly the blockage is. The pvc pipe is long, all the way to the outside. Which section is mostly like causing the trouble?

Another question, you can see a curved section on the drain pipe in the picture, is it necessary? Can I just replace it with a straight pipe?

My suggestion is to cut it between the threaded fitting and the elbow. Now if this does not allow you enough room to install a coupling or the safety tee I mentioned, you might have to make another cut in the straight section to shorten the line so you have more room to install the tee or coupling.

As for exactly where the blockage is, my experience says that it will most likely be in the trap(that is the curved section), but can be at any elbow or place that would slow the flow of water. That curved piece is called a trap and yes it is necessary from proper draining. While you have it open, you can look inside the fitting and clean anything that might be there.

Although you can see the threads. you can not unscrew the fitting without cutting as the entire drain would have to unscrew along with the fitting (There is no union for disconnecting).You could also install a union if you choose to make it possible for future issues to open rather than cutting if it blocks up again.

All of these fittings are rather inexpensive. You can get the safety tee I mentioned for about 15 bucks .Couplings are less than a dollar each and a union is about 3 dollars. Remember though to glue everything back together.

Customer: replied 4 years ago.

ok, sounds good.

Please follow up and let me know if this solves your problems.
airheatman, HVAC Technician
Category: HVAC
Satisfied Customers: 8326
Experience: Furnace, A/C and heat pump specialist.
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