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Troubleshooting help needed! LG mini-split leaking from air outlet

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I installed an LG mini-split, 4-zone less than 1 month ago, and one of the zones is dripping water from the air outlet.

I have poured water over the evaporator and it drains fine. There does not appear to be icing of the evap. Air filter is clean. Any other ideas?

The unit installed is a
LMU30CHV ODU
LSN120HSV5 IDU - leaking unit
LMN079HVT IDU - (x3)

Comments

  • ratio
    ratio Member Posts: 3,654
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    High humidity in the space with the dripping head? It's my understanding that mini split heads don't shut off refrigerant flow completely due to oil control issues, so that head may be getting overcooled in the wrong places & condensing in places it shouldn't. Also check the heat gain vs head size. Does it satisfy? Is the temp set to something unreasonable?
  • motoguy128
    motoguy128 Member Posts: 393
    edited August 2020
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    We only sell Fujitsu, but I’ve never seen this. Only leaking has been kinked, plugged or inadequate Drain pitch on a long lineset. But you said it drain fine when water poured on it.

    Is it in a room that’s really humid? Wall sealed behind the unit? I wonder if humid air is condensing on the louvers. Same thing happened to conventional system with ceiling registers below hot/humid attics. The metal is 50F and humid air drawn across the ceiling will condense on it.


    Actually I believe most dust accumulation on wall mount minisplit blower wheels is actually form dust in the room, not return air.

    So if hot humid air is in the room at the ceiling, it may be condensing on the 45-50F plastic louvers or just inside the fan blower shroud.
  • bio_guy
    bio_guy Member Posts: 89
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    When this happens with ducted systems that cycle, bang bang, on and off, is the condensing happening when the blower is running or off? If the latter, it does not really apply to mini splits that have the blower wheel turning all the time, does it?

    If the unit is cycling rather than just throttling back, the coil could be warming up above the dew point faster than the downstream plastic bits. If that is happening, the cold plastic bits could be getting hit with air that is very saturated since the blower does not stop completely.

  • jamesbeardiv
    jamesbeardiv Member Posts: 4
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    Dang, I've been fighting the same problem with the same LG unit for since around the same time.  Also have a couple 9K unit that drool from the blowers for no sane reason.

    I wonder if anything actually solved the problem.  I'm about to throw my hands in the air and replace an indoor unit to see what happens.
  • EBEBRATT-Ed
    EBEBRATT-Ed Member Posts: 15,634
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    It's probably the condensate drain hook up.

    You have to be careful that the drain pitches down hill. If you use plastic tubing especially.

    If you have more than one trap in the line with an air bubble in between the condensate will not drain well.

    The drain can only have 1 trap
  • jamesbeardiv
    jamesbeardiv Member Posts: 4
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    I can tell it's 100% not the condensate drain.  They all function perfectly.  Heck, unplugged the drain and let it run from a clear hole to a bucket, still drools.  I've tilted the drain every which way.  In fact, the only "fix" I have achieved is Duct Tape in the area of the evaporator unit where the condensate seems to drip into the blower on one unit (blocking all air to that exact spot).

    I've pulled the drains on both sides, so they could drain from either side, replaced line sets, checked charges, other techs came out and shrugged.  

    Now the funny thing is that one year later, the unit that was delivering the worst of it hasn't shed a drop, while the back bedroom (which I never saw drool until after we tried redoing the line sets in case of restrictions) now drools like an English Bulldog.

    Could it possibly be a contaminate within the lines that got inside these indoor units?
  • jad3675
    jad3675 Member Posts: 127
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    I can tell it's 100% not the condensate drain.  They all function perfectly.  Heck, unplugged the drain and let it run from a clear hole to a bucket, still drools.  I've tilted the drain every which way.  In fact, the only "fix" I have achieved is Duct Tape in the area of the evaporator unit where the condensate seems to drip into the blower on one unit (blocking all air to that exact spot).

    I've pulled the drains on both sides, so they could drain from either side, replaced line sets, checked charges, other techs came out and shrugged.  

    Now the funny thing is that one year later, the unit that was delivering the worst of it hasn't shed a drop, while the back bedroom (which I never saw drool until after we tried redoing the line sets in case of restrictions) now drools like an English Bulldog.

    Could it possibly be a contaminate within the lines that got inside these indoor units?

    No. As others have stated before in this thread it is probably because of high humidity and really cold plastics bits. How is the air sealing around the minisplit head itself? Outside/inside wall? Is it insulated?

    John

  • EBEBRATT-Ed
    EBEBRATT-Ed Member Posts: 15,634
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    @jamesbeardiv

    The minuite you say it's 100% not a condensate problem your getting tunnel vision. It is a condensate problem, it's leaking water. Is the condensate problem caused by another issue? Like a refrigerant issue/ Maybe

    What indoor temp are you running at? What is your suction pressure?

    If you run the indoor temp below 70 you can have issues
  • jad3675
    jad3675 Member Posts: 127
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    @jamesbeardiv

    The minuite you say it's 100% not a condensate problem your getting tunnel vision. It is a condensate problem, it's leaking water. Is the condensate problem caused by another issue? Like a refrigerant issue/ Maybe

    What indoor temp are you running at? What is your suction pressure?

    If you run the indoor temp below 70 you can have issues

    It's a minisplit. Suction pressure doesn't matter.

    It is a condensation problem though, just not condensation off the coil.

    Here - I have ducted minisplits in my house. It's a cape cod with marginal insulation on the roof side so the upstairs is always a bit stuffy. My units are in the knee wall space which is decently insulated, though. I have the unit in my office on the second floor running right now, set to 68. Vent temp is 45F. I have the windows downstairs open, though, because I like cooling the neighborhood. This is the only unit I have running.

    But guess what? Due to the humidity in the air, I'm getting condensation on the metal air grates in the wall.



    If I had the downstairs units running, I wouldn't be seeing this issue - and that can be an issue with minisplits. You're spot cooling and dehumidifying one area, while leaving the rest of the house alone.

    Something similar is happening to the LGs in this thread - the front fascia of the unit is cold enough for the air to condense on it. Is this the only unit running? What's the humidity like in the rest of the house? return and vent temps?

    John


  • Big Ed_4
    Big Ed_4 Member Posts: 2,807
    edited May 2021
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    Looks like that ductable mini has air leaks and lack of duct insulation . Was it programed for the actual pressure differential ? For the amount of duct work used ...

    On the wall units did you seal up access hole you made in the back ?

    Mini splits condensate drains are low pressure high volume ... Any traps down river will cause a problem . , Down and out with the drainage .

    There was an error rendering this rich post.

  • jad3675
    jad3675 Member Posts: 127
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    Big Ed_4 said:

    Looks like that ductable mini has air leaks and lack of duct insulation . Was it programed for the actual pressure differential ? For the amount of duct work used ...

    You'd be wrong - duct work is sealed and insulated. The ductwork is well within specs for the air handler too. I was just trying to show that the environment can cause the sweating that he is seeing - if you set one head really low and have the rest of the house not quite sealed up - guess what? - the humidity will go to the cold and (surprise) condense there. That has to be what is happening here. As you asked, how is the air-sealing behind the installed head unit?

    John
  • EBEBRATT-Ed
    EBEBRATT-Ed Member Posts: 15,634
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    Running any AC below 70 degrees is rediculuous. Look at any design information and indoor design temps for comfort cooling and they usually design for 74, 76, 78 degrees. If you not comfortable at those temps you have humidity issues.

    The reason you get sweating when only a portion of the house is cooled is your dropping below the dew point. Humidity is transferred much faster than sensible temperatures
  • Preiss
    Preiss Member Posts: 17
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    I have a ductless 18k unit upstairs. When I first installed it I ran it below 70 F and the blower full out. With so much initial humidity in the house the poor little evaporator was sweating like crazy. Even though initially condensate was dripping like crazy into the tray and away, the evaporator was saturated and with the blower on full tilt, water was actually splattering onto the louvred which looked like a leak to me. I changed the set point above 70 F and slowed the blower down. Once the upstairs humidity lowered a bit I was able to turn up the blower and all stayed good. If your set point is too low and blower too high, try adjusting those first. If you don’t see an improvement you might have an undersized head. Just a thought.
  • jad3675
    jad3675 Member Posts: 127
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    Running any AC below 70 degrees is rediculuous. Look at any design information and indoor design temps for comfort cooling and they usually design for 74, 76, 78 degrees. If you not comfortable at those temps you have humidity issues.

    The reason you get sweating when only a portion of the house is cooled is your dropping below the dew point. Humidity is transferred much faster than sensible temperatures

    Sigh. Again, I was demonstrating exactly that - showing, yes, you can get external condensation from a minisplit system that has jack to do with the condensate removal system. Man, here I thought I was being helpful - obviously I wasn't. :)
  • pecmsg
    pecmsg Member Posts: 4,895
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    jad3675 said:

    Running any AC below 70 degrees is rediculuous. Look at any design information and indoor design temps for comfort cooling and they usually design for 74, 76, 78 degrees. If you not comfortable at those temps you have humidity issues.

    The reason you get sweating when only a portion of the house is cooled is your dropping below the dew point. Humidity is transferred much faster than sensible temperatures

    Sigh. Again, I was demonstrating exactly that - showing, yes, you can get external condensation from a minisplit system that has jack to do with the condensate removal system. Man, here I thought I was being helpful - obviously I wasn't. :)
    I agree
    People think because there variable speed they cant be oversized, completely wrong. The equipment is fine if multiple heads are calling but if there only running 1 out of 4 can the outdoor unit ramp down low enough?
  • EBEBRATT-Ed
    EBEBRATT-Ed Member Posts: 15,634
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    @jad3675
    What you said was fine. I agree.

    Most customers don't realize that comfort cooling is not refrigeration. They want to turn their house into a walk in cooler....or freezer.

    Force the equipment to run outside of what it is designed for doesn't work so well
  • jad3675
    jad3675 Member Posts: 127
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    I agree
    People think because there variable speed they cant be oversized, completely wrong. The equipment is fine if multiple heads are calling but if there only running 1 out of 4 can the outdoor unit ramp down low enough?

    You think if they spec the outdoor unit to run a single head @ 9K BTU, that it would be OK...
    John

  • pecmsg
    pecmsg Member Posts: 4,895
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    Depends on minimum and max loads. 
    We stopped installing anything larger then duel zone. 
    jamesbeardivSuperTech
  • jamesbeardiv
    jamesbeardiv Member Posts: 4
    edited May 2021
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    Current tech was stumped, but came to the same conclusion as myself.  Were swapping a indoor head soon.  Just isolate and then chop so if anything is in there it stays. I know that the goob that installed it used that anti leak crap on the lines (bad no no I realize now since it can potentially get in the lines).  So I'm suspecting could be some of that trash got in the lines.   Just makes since realized that one machine I was almost ready to rip from the wall it was so bad now works perfectly, and over fall and winter when I use a different unit more now has inherited all the all the other indoor units problems.

    Now, I'm wondering if I have to use the zones on order, of if I could put the bad unit on the unused zone 4 to rule out a contaminate having effed the EEV.

    I enjoy a nice comfy 70-72 myself.

  • jamesbeardiv
    jamesbeardiv Member Posts: 4
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    Update: After replacing the indoor head with a new indoor head, and putting the replacement into zone 4 (thereby bypassing what I believe to be a corrupted EEV on zone 3).  The problem seems to be solved for one indoor system.

    Will never know if it was a corrupted evaporator unit or a bad EEV - I suspect both.  But I still have 2 drooling indoor units to experiment with.