Condensation is dripping into overflow pan

13 years ago

I have a newly installed AC. The bottom of the enclosure around the coil gets cold enough that it is always below dewpoint and most of the bottom nearest the primary drain is wet.

There is enough condensation to cause puddling in the overflow pan. The contractor claimed this was normal. There is maybe a half cup of water inside the enclosure pooled at the primary drain. Then there is another half cup or so of liquid in the overflow pan.

The reason I am concerned is that the condensation is occurring where the coil transtions to the plenum. The transition from coil enclosure rises about an inch in the transition to the plenum. Condensation also occurs on the underside of this transition area which angles up at about 30 degrees and mostly runs back to the overflow pan, but a bit drips onto the attic insulation under it. The insulation is barely damp on top of the fiberglass bat.

The old system never did anything like this. Is this something that needs to be fixed. It just does not sound right. Thanks for any help. I am just a homeowner trying to understand this new system.

Edit/Delete Message

Comments (6)

busboy
13 years ago
Condensation should not be dripping into the pan at all. The pan is the backup telling you that something is wrong in your drain line. I had a similar overflow problem in a new installation. There is normally a trap installed in the line to prevent backflow into the blower unit. However, if after the trap the line does not continue horizontal or down, ie angles up for a short time and then down it will in effect form a SECONDARY trap. An air column will form between the first and second traps thus blocking any water from draining through the first trap and thus overflowing. Basically.. everything before and after the trap must go downhill. In my case the secondary trap formed in the basement ceiling at a right angle because they pushed the vertical drainline down too far in the new installation. I discovered it when the pan overflow drain outside started dripping. IE the overflow worked and alerted me to the problem
nobhill
Original Author
13 years ago
Thanks for the info.

In my case the drains are functioning properly. This is just condensation on the bottom of the case for the coil. It is cold enough that is is always below dewpoint. I have never seen anything like this and am puzzled.
Related Discussions
Drains for poly drip pans + gritty mix?
Q
Comments (14)
Here's a simple method I used after quite a bit of trial and error. For 1/4" dripline: I drill a small 1/8" inch hole and then grind the hole bigger using a spike nail. This gives the hole a taper. Then cut the 1/4" tube at a slant and pull through. Never had a leak with this and have used with hard and soft plastics. for 0.600" poly tubing: You need to be more careful for these ones. I first drill a small 1/4" hole. Then I use a stone grinder attachment for the drill to drill the hole bigger. The grinder heats up the plastic and partially melts it. This prevents the plastic from cracking. If you just use a big drill bit, it will crack the plastic from pots and tubs (rubbermaid plastic garbage cans don't crack though). Make the hole significantly smaller than the 0.600" tubing (or whatever tubing you use. Make 4 1" long slices in the end of the tubing with a razor knife. This makes it easier to insert into the hole. Then heat the tubing by holding it against a 100 watt bulb for about 30 seconds, this makes it more flexible. Then insert the tube into the hole. This makes a nice waterproof connection without grommets or bulkheads. When I first did this I didn't heat the tubing and had to make the hole bigger to push it through, this caused leaks. In this picture you can see the stone grinder tool I used. I plan to post a complete description later. regards
...See More
AC Condensation Overflow
Q
Comments (4)
Don't use bleach on a clogged line. It won't clear it and will just cause corrosion on what ever metal it come in contact with and can also accelerate corrosion of the coil in some cases. You really need to get a hvac company out to check the drains and clear the lines. Rust in the auxillary pan means this has happened perhaps a few times before. A properly install main drain will have a tee in it before (capped) and after a trap (capped or uncapped) where you can see if and where the drain may be clogged and perhaps use air pressure to see if that will push the obstruction thru. Other causes could be a system that is icing up, a cracked drain connection, a rusted pan and some systems (carrier) have a metal drip catch on the horizonal units to guide the condensate to the main pan that when dirty runs the water over the coil into the duct. It's probably just a clogged drain, but as you can see there may be more to it that may need attention. *I've had to replace many an indoor coil because it rusted out prematurely due to chlorox used the wrong way.
...See More
sudden condensate pan overflow and shutoff??
Q
Comments (9)
The most likly culprit is alge and dirt restricting drain line. Even trained techs can't rule out line restriction by visual inspection alone. It is customary or should I say should be, to clean the line when the tech does annual maintnance. It sounds like you are willing to diy maintainance and I for one believe it's possiable for the owner to do a better job than they will recieve from many contractors. So here you go. First off,it's likly the origional drain line is still in place from the closet to sewer connection. Pressurizing the line to force debris out can be done with a"FAT"tire valve stem with the schreader removed and portable air tank. Adding water and blowing out line repeated 2 or 3 times can be benificial. Putting an algaside in the pan/drain quarterly is a good preventive measure. The common home remedy is 1 oz laundry bleach diluted in 6 oz water. A word of advice. If cooling is not used for 30+ consectve days,discontinue bleach at least a month prior to discontinued use and don't treat with bleach during periods of intermentant use. Bleach is mildly corosive if alowed to remain in the pan for long intervals. Condensate will flush out the pan while in use. There are tablets specifily for hvac condensate use but some of those are more corosive than bleach so use what you may. Unless you operate a woodworking shop inside your condo,30 day filter changes is overkill. If you are useing 99cent filters,they are better than no filter at all but just barly. At minum,use the cheapest pleated filter(about $3 ea) you can find and above all,make certain it fills the rack alowing no air to bypass filter. If you have respitory or sinus problems,step up to a $8 to $15 micro filter. You will not harm the unit by changing filters every month but one good filter less often is far better than half dozen el-cheapos over the same period. There is not a majic interval. A good house keeper that doesn't have pets or younguns bringing in dust might be fine with 6 month intervals. Your filter will have a destint grey fuzzy coating if retained for maximum time. That should go a long way on preventing condensate drain problems and afford some bonus rewards in the process.
...See More
Problems with Kenmore side-by-side Refrig, pan underneath overflowing
Q
Comments (1)
You may want to also post to the Appliances forum. Good luck!
...See More
daddo
13 years ago
There can be a little sweat in areas of very high humidity, especially if it is in an attic, but should not be a lot of water.
If it is in a closet- check that closet is sealed well from hot humid attic air and in both cases, the insulation inside the coils case has not been damaged.
nobhill
Original Author
13 years ago
Thanks for the tip. I will check more closely. My main concern is that there is condensation from the plenum downstream of the coil housing.

It isn't much but it drips onto the insulation in the attic. Not a huge problem, since it is so little, but there is no pan under it so I am concerned about it long-term. This just doe not seem right.

Thanks for the tip.
energy_rater_la
13 years ago
is the plenum sealed to the coil on top bottom and sides?
I often find that the bottom of the plenum is not sealed
to the coil. cold air meeting hot metal condensates.
water dripping into your insulation can cause a lot of issues.

best of luck
nobhill
Original Author
13 years ago
Plenum is sealed but I will check closely to see how well. Just found where two new flex ducts touch and there is condensation there too. I will move them apart. They only can have about an inch of space between them - and hopefully that bit of separation will at least solve that.

THANKS for the feedback. This is all VERY helpful. I am learning more about HVAC than I ever intended to, and it is all to my benefit.

I have new respect for the professionals. HVAC these days is much more complex than ever before, starting with those dedicated-purpose computers on the wall that are still called thermostats...

Condensation is dripping into overflow pan

Comments (6)

busboy

nobhill
Original Author

Related Discussions

daddo

nobhill
Original Author

energy_rater_la

nobhill
Original Author

COMPANY

BUSINESS SERVICES

GET HELP

CONNECT WITH US

Condensation is dripping into overflow pan

Comments (6)

busboy

nobhillOriginal Author

Related Discussions

daddo

nobhillOriginal Author

energy_rater_la

nobhillOriginal Author

COMPANY

BUSINESS SERVICES

GET HELP

CONNECT WITH US

nobhill
Original Author

nobhill
Original Author

nobhill
Original Author