Why is My Mini Split Leaking Water? - Ask the Expert Episode 175

Questions about a ductless mini split leaking are common. But the issue is often very easily fixed. Let's hear what Dan Danowski has to say about it.

Judith asks, "Why is my Ductless Mini Split leaking?"

"Hey Dan, my ductless mini split leaks water inside the house and down the wall. A lot of water. The unit is set on cool mode at 75 degrees. It has done this three times now. The water in the drain hose seems to be full of water. I shake it to get it out. It seems to suck what's left back up the hose. What can I do to fix this?" The issue for your ductless mini split leaking seems pretty straight forward. The drain hose is probably not angled downward properly. You definitely shouldn't have to shake it to get the water out. It also shouldn't get sucked back up the drain hose. You might need to fiddle with it a little bit, though. The water drains out because of gravity. So the drain always needs to be going downward. If for some reason you can't do it that way, like you have to go up over something to get the drain hose out of the house, then what you need is a condensate pump. Condensate pumps go inside the air handlers on mini splits and they pump the water out. That's why they are called condensate pumps. Have more questions about a ductless mini split leaking? Just ask them in the comments below or on Facebook or on Twitter. 
Comments
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Kenny Ziesmer
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Why is my 2 ton mr cool heat pump have water coming out with the air and dripping off the louvers drain pan is empty off water it is draining
Kyle
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The biggest reason any mini-split leaks water is a clogged drain line. Make doubly sure yours isn't clogged. If that doesn't fix it, call us at 270-575-9595 x300, and our tech guys can walk you through some options.
Victor
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I have an older Mitsubishi Mr Slim mini split. Came with the house. About a week ago, I cleaned the filters. Three nights ago, I noticed water dripping from the vents of the wall unit. This went on for two nights, but the unit was cooling. Last night, the unit would not cool. The drain pipe is pitched at the right angle and I haven't noticed ice buildup on the condenser (thought I haven't ruled it out). Could the water drip have damaged the unit?
Steven
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The water drip is just condensation. Is the internal drain pan overflowing, or maybe has a crack in it and is leaking? Either way, it shouldn't have been the cause of damage to the system. You should call a local HVAC tech to come out and diagnose the issue.
grego
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I have a mr cool mini split in my basement shop on an interior wall. It's hooked to a condense pump about 5 ft away. The drain line definitely has slope, but it has backed up leaking water all over the stuff under it about 4-5 times now. I have noticed some slimy sludge in the line. It did it again this morning. I pulled the cover off and the condensate line and cleaned it as best I could. Do any of the condensate drain pan/line treatments work at keeping the slime/sludge form clogging the drain line?
Kyle
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Yes, we have seen this kind of thing before. You can clean the line with a mix of bleach and water every few weeks to clear it out. We've also seen good results from drain pan tablets. You should also check to make sure that the line has no "swags", at least 1/4" per foot drop, and that the drain line is not immersed in water at the pump chamber.
Nathan Angle
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I just installed a mr cool 12000 diy unit. Turned the cool on and after about 10 mins the indoor unit started to leak water.
Dan Danowski
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The water is not draining out of the air handler properly. There could be an obstruction in the drain line or the air handler is not properly leveled. It's probably the former.
Julie
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Hello, I have been in this house about 10 months. It came with a Carrier 40MHH High Wall Ductless System. About a month or so after I moved in during summer months, I had a water leak event under the unit, about a quarter cup of water. Previous tenant said she'd never had that happen before. About that time I was also getting an error code, so I called a repairman. He cleaned the filter and said everything checked out fine. Turned out the remote needed new batteries which I replaced. Been working fine until last night when I had another leak event. I noticed the cooling hasn't been working very well the past couple of weeks. We haven't had any real hot days, but usually this unit will make it super cold very fast. Last night we had a cold front come through, raining outside and cooler outside than inside, A/C was on set at 70. Last night it started making a loud pinging noise like metal on metal and that's what got me up to see the water dripping down. I shut it off and this morning turned it on and ran the "Self Clean" function, which seemed to work fine and no more water dripping down. Had no problem with the heating function last winter other than it seemed to need to go into defrost mode fairly often. Before I call the repairman again, can you please give me any suggestions as to what is causing the water leak. The unit is only probably about 18 months old. Thanks so much!
Dan Danowski
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It's not so much a water 'leak' as it is condensation forming on the coils and then not being drained out properly. The unit might not be properly level, or the drain hose could be clogged/obstructed in some way as to prevent the outflow of water.
Angela Hamilton
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Just had a used (2 year old) mini split installed. Seemed to work fine the first night but the second night it started to leak intermittently. I turned it off right away but hours later, it’s still leaking smaller amounts every few minutes. Any ideas? Also, who would I call to fix this?
Dan Danowski
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The 'leak' is most likely an overflow of the drain pan in the air handler. This could be due to a clog in the drain hose or the air handler is not perfectly level. Check that the drain hose is draining properly. If not, contact the installer.
Rodney
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I have an 18000 Mr. Cool DIY. Do you have a video link on how to get to the air handler drain pan so I can clean and maintain it?
Dan Danowski
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We don't, but that is a good idea for a video!
Richard Prest
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Hello, I have a 18000 mini split , condensate drain works great but not on dry mode. Is it just to much water to handle ? Thx
Dan Danowski
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I suppose that's possible, but I would check for a blockage. And ensure the air handler is properly level.
Clayton Perrey
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Do you have a recommended type drain pain tablet? And - how do you get them into the drain pan?
Rebekah Muller
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We do not have any that we specifically recommend.
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