Mini Split Air Conditioner Leaking from the Indoor Unit.
June 16, 2010 by Shawn Mack
Filed under Ask Thomas
First Name: Eric
Last Initial: B
Equipment: Mitsubishi Mini Split Air Conditioner
Problem:
The mini split AC unit cools beautifully. However, anytime we set the temperature below 70 degrees, we will get water dripping from the inside unit. This is not condensation water dripping from the vents - it is water coming out from the unit. This unit does have a drain tube to the outside and it does work properly. Could this water problem simply be a result of the drainage tube freezing? If so, is there a solution. It defeats the purpose of the AC unit if you cannot make it cool in the house. Any responses are appreciated.
Solution:
There are two possible solutions to prevent leaking from a mini split air conditioner indoor unit. One: There is a blockage in the drain line or the drain line is not installed properly and gravity cannot rid the system of the condensation build up. Two: The drain pan inside the indoor unit is level and water cannot drain, via gravity, out the back of the system and down the drain line. Most units will need to be installed with a slight declination towards the drain line side. This lets the water flow downward and out of your conditioned area. People see leaking indoor units on very humid days when the drain pan fills more quickly and cannot terminate the water fast enough because of the drain pan being level. I tell my customers to tilt the indoor system 1/8″ down towards the drain line at the time of installation.
August 1st, 2010 at 10:12 am
I have a similar problem, but it is not related to either solution. (A/C temperature set to 70*) Condensate line is working properly. I noticed water droplets dripping from behind the fan inside the main unit. I was able to get an automotive telescopic mirror up inside and behind the fan (duct) and I could see part of the evaporator exposed.
I live in Orlando and it seems to be very hot and humid this season. Obviously, the water condensing on the evaporator is not draining fast enough and some water is dripping straight down in to the fan duct. Any suggestions to a solution?
June 17th, 2011 at 9:40 am
Thanks so much for this. I had no idea about the drain pan so, when mine started leaking I was freaking out. Cleaning the filters then tilting the drain pan worked a charm and it only took 20 minutes. Saved me calling my maintenance guy
July 6th, 2011 at 4:00 am
To Nick S. :
I have the exact same problem with my Ramsond indoor unit. The condensation is coming from somewhere behind the fan and trickles down to the front of the unit where it drips out and onto the floor. The drain pan and tube appear to work properly as the condensation in the pan never overflows. The problem does seem worse on hotter and more humid days but it is so bad that I really cannot use the unit. I will be contacting the manufacturer today to see what can be done.
August 2nd, 2011 at 6:14 pm
Dan– We have a Mitsubishi minisplit unit that is doing the same thing. The drain is working and no water builds up in the tray. But the unit is basically unusable because of all the water that is leaking out. We’ve had the unit installed and working beautifully for 3 months (and it’s been 90 degrees and humid most of that time) until this just happened. Have you come upon any solutions? Company tech support has thus far been unable to suggest a solution.
August 17th, 2011 at 3:22 pm
I have an LG split unit ac that is maybe two months old. The unit is slanted to drain and the drain works. Im getting an oily substance on my wall thats definately not water and when i pop the bottom up to check it there is oily stuff on the lip underneath for the left two thirds of the unit. It drains on the left. I would appreciate any advice.
August 17th, 2011 at 5:11 pm
Jason, I have the same issue with a Sanyo, as well as the water issue that everyone else here has written about. The oily substance my AC guy said, “it’s just from fat and stuff in the air from the kitchen that gets pulled into the unit.” I’m not buying it. The oily substance is on the vent lip underneath, and I actually get specs of dirt and stuff under the unit. It has been installed seven years. The oil has been present for the last three or so, and the water all over my lamp and couch started today. It has been damp here lately, but I’m shocked that this unit could basically just pour enough water out of itself over a day that it drenched my lampshade and couch. No idea what to do next.
August 21st, 2011 at 9:50 am
I have had the same issue. It turns out that the refrigerant in the unit was very low. After having a friend who is a tech come out and look at the unit it was determined it needed 2 pounds. The system holds 4.6 pounds. Once done, no more condensation.
August 25th, 2011 at 4:36 pm
I have an LG mini split in basement. Have been experiencing some leakage from the middle of the unit inside my room when unit has been running for 2 hours. It seems to be draining fine with no blockage. Originally leaked out of the left side of unit (when facing unit). Readjusted and hasn’t dripped from either side except the middle. Had all the lines reinsulated as the refrigerant lines run through a crawl space that has been conditioned. Still humidity in basement but nowhere near the outside. Plus I have a dehumidifier in crawl. It seems that the leak is coming from the middle where the tubes for refrigerant enter the unit. Any suggestions?
September 8th, 2011 at 1:34 pm
I have a similar problem with a Mr. Slim unit. The drain pan fills at times AND have had to have it recharged three times. It turned out that there was a leak in the evaporator coil as well as at the connections to the line set.
Unfortunately for me, Mitsubishi will not honor the warranty because it was installed before July 4, 2008. The newer units carry a 5 year warranty. I don’t consider 4 years of use to be a normal situation.
September 22nd, 2011 at 1:09 pm
anyone getting an oily substance runningg down their walls should call the installers immediately. this oily substance is in the coolant lines. this means your fittings are not tight and you are losing your coolant. They should tighten all line connections and recharge your coolant. Do not let them leave until they recharge your coolant.
October 11th, 2011 at 2:15 am
How do you find the drain pan? I can’t get to anything but the filter on mine. Granted it’s Multiline not Mitsubishi…but if any of you can tell how you got to your drain pan, mine’s got to be similar…
November 1st, 2011 at 1:18 pm
We have a Fijitsu split air unit here in PR it stated leaking water like crazy yesterday, how do I check the drain hose or pipe?
November 25th, 2011 at 12:33 am
Hey Guys, the indoor unit had just leaking now. I open unit cover and found a small water container. It was open top container. Maybe it design like that to spill the water if it gets full.
I thought it was because dirty drainese but then i found a corrosion rust chip and thought that the chip was blocking on the middle of the container because the left water level on container was different with the right water level on drain gate.
So I put some hose on the left and blow it until all the rust chip that get stuck going out to the drain out gate.
After that, it is not leak again.