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Air conditioner dripping on inside
Our air conditioner occasionally drips on the inside.  It normally happens when the fan is set on auto.  As the fan cycles to off, we get a small stream of water at times...not consistently.  We are currently on the Texas coast with high humidity making the drip more common.  It seldom happens when the fan is on high.  Any suggestions to correct the problem would be appreciated.
Ross Taylor
2017 MB
Re: Air conditioner dripping on inside
Reply #1 –
I’m no expert on this but I wonder if the drip tube (if there is such a thing/I think there is) has cracked, broken off from the AC unit.

I have a faint recollection that a drip line travels down past/through the refrigerator compartment and to the ground. [Edit: Nope, there isn’t a drain tube but instead a drip pan. ALSO: There is nothing in our LDmanual about an issue about dripping or overflow-Although the maunufactures manual may cover this].

If this is the case and water is entering your rig (not a good thing), your wooden framing is most likely getting wet which could be a real issue.

I’ll check my manual and see if I can locate information in these regards. In the meantime, Larry, Chris, Steve and Joan probably have your answer.

I just found this YouTube video that addresses your issue. Seems to have your answer.  https://youtu.be/Ty-j9iT6YL8

Stay dry.

Kent
2015 27' RB "MissB.Haven"
Re: Air conditioner dripping on inside
Reply #2 –
This may help:

R.V. Air Conditioner Leaks

I'd first check the seal/gasket for tightness (if it's loose or too compressed, water may leak into the RV) and the drain pan (under the evaporator) for clogs; if the holes are blocked, water can drain into the rig instead of draining away on the roof. Not leak causing, but I'd also make sure the air filters are clean while you're at it; just rinse them under gently running water and let them dry thoroughly before putting them back.

You will likely get additional "answers" and input; please post the solution when you find it.
2003 TK has a new home
Re: Air conditioner dripping on inside
Reply #3 –
Assuming it isn't raining, dripping can be caused by a plugged evaporator drain.
The cold evaporator condenses moisture out of the passing air, the condensed water is then drained out to the roof. If the drain is plugged, the evaporator's reservoir will overflow into the interior.
Without looking at the unit, I have no idea how to clear the drain tube(s).  You might give the Mothership a call or see is the A/C's owner's manual has more information.

Larry.
Larry
2003 23.5' Front Lounge, since new.  Previously 1983 22' Front Lounge.
Tow vehicles  2020 Jeep Wrangler Rubicon, 2001 Jeep Cherokee
Photo Collection: Lazy Daze
Re: Air conditioner dripping on inside
Reply #4 –
I just finished with a Dometic approved repair service.  The air conditioner discharge was building up condensation on supply side.  Their was no insulation between the air supply and return and the duct was very thin.  All this and very humid area caused the condensation buildup similar to a window when it is warm on one side and cold on the other side.  They put additional insulation between the supply and return and used 3M air conditioning tape to beef up the duct.  They also recommended running the a/c on high until we get out of this humid area.
Ross Taylor
2017 MB
Re: Air conditioner dripping on inside
Reply #5 –
It does not do it on HIgh. Right. There ya go.
Don & Dorothy
Sold our LD in June of 2023

Our boring always non-PC travel blog
Traveling Dorothy
Re: Air conditioner dripping on inside
Reply #6 –
Still working on problem.  I will post again when I know we have solved the issue.
Ross Taylor
2017 MB
Re: Air conditioner dripping on inside
Reply #7 –
I had this issue on 1 extremely humid weekend, ran AC constantly and when we shut it down to depart it dripped rapidly for a few minutes. Tore the AC apart from inside the coach and from the roof...couldn’t find any source of leaking or clogged drains. Hasn’t happened since but I assume the issue was condensation within the ducting that leaked back. This phenomenon must only occur at a specific ambient temperature/humidity.
2000 RB
Re: Air conditioner dripping on inside
Reply #8 –
Last night while camping in Acadiana Park in Lafayette La.  I had that dripping water off the AC unit inside.  Temperature was 90 or so and humidity 98 and up.  I was running the AC on auto.  Today I'll run on Medium or High to see if that fixes the issue.  
personal fine art photo stuff
TF Mack | Flickr
It's all good .......
2014 Twin King
Re: Air conditioner dripping on inside
Reply #9 –
Lafayette LA is my hometown, I’m jealous!  Make some time to eat some great Cajun and seafood!
Nov 2023, 2012 31’ IB, white/green swoops & swirles, 2009 Mini Cooper, racing green convertible, toad 🐸

We ordered white/gray  2018 27' mid bath 1/3/18 and we are hoping for a July 16th 2019 delivery, sold, and tried a Lithium Travato, wish  I would have kept the Lazy Daze 27’
Re: Air conditioner dripping on inside
Reply #10 –
Quote from: colddog  - 
Last night while camping in Acadiana Park in Lafayette La.  I had that dripping water off the AC unit inside.  Temperature was 90 or so and humidity 98 and up.  I was running the AC on auto.  Today I'll run on Medium or High to see if that fixes the issue. 
We always talk about following the weather. What are you doing in the Southeast this time of year?  ;)

Chris
Formerly: 2002 30' IB
Re: Air conditioner dripping on inside
Reply #11 –
The additional insulation installed helped, but running the fan continuously was the solution.  It did not matter whether the fan was set on low, medium or high, just NOT on auto.  Apparently, when auto fan is selected the fan cuts off when the compressor does leaving any condensation on the supply to accumulate and drip or run out.  With the fan being left on, the condensation has a chance to dry out before the compressor comes back on.
Ross Taylor
2017 MB
Re: Air conditioner dripping on inside
Reply #12 –
An understandable article on RV air conditioners.

By Steve Savage, Mobility RV Service
This time of year we get calls for air conditioner service. Often the caller is all worked up because he or she thinks that since their air conditioner has stopped working, there must be something seriously wrong. That’s often not the case — it’s often just a freeze-up.

The scenario for an air conditioner coil freezing up goes something like this. Your air conditioner or air conditioners were working and gradually, over the course of a hot day with high humidity, airflow out of your ceiling vents first drops off and then falls to zip. Finally the compressor may stop running and it seems as though the air conditioner has quit. What is going on?
The giveaway for the diagnosis in this case is the airflow slows and then quits entirely. That sequence of events is not the signature of fan motor failure — it signals ice buildup on the evaporator coil inside your air conditioner. For those who have never looked up into their air conditioner, if you removed the filter you see from inside your RV and look up into it, you will see a finely finned cooling coil. That is the evaporator coil and it gets very cold — so cold that it approaches the freezing point of water. It is the water running down that coil and into a drain pan that drips off the roof of your RV when the air conditioner is running. You can only see it from inside your RV so there is no need to go up onto the roof and take the cover off the air conditioner. You can fix this problem from inside your RV and best of all, you do not need any tools.
First, a little bit more about what causes coil icing. The first thing an air conditioner does is remove what is called “latent” heat, also known as the humidity from inside your RV. It does this by circulating air into the return and across the cooling coil, where humidity condenses out and runs off the roof of your RV. On a humid day there can be so much moisture, if the fan is running on low speed, some of the water on the coil will start to freeze. When this happens and the coil becomes partially blocked, the freezing is accelerated and more and more of the coil freezes, and less and less air passes over it until the coil is completely iced over.
When the coil is iced over, air delivery to the vents is blocked and, if enough of the coil freezes up, the freeze protector that serves to protect the compressor from operating with an iced coil closes or opens a circuit (depending on which manufacturer’s air conditioner is on the roof) and the compressor quits running. So there you are on a blazing hot day with no air coming out of the vents and no compressor operation.
If the above is you, do this first. Remove the filter cover so you can see the coil. It will be sheeted over with ice. If you cannot see the fins, it is surely iced over, but you can also put your hand on the coil and feel the ice. The coil cannot harm you, and you will not harm the coil by touching it.
Feel the ice? If you can, you just got lucky. Go to your thermostat and switch the “mode” to “fan high” instead of “cool” and give it a few minutes (how many minutes depends on how much ice has built up). Two things should happen. The air coming out of the ceiling vents will gradually increase and you will hear the ice dropping off the coil and into the pan. You might also get some water dripping out of the filter cover as the ice melts. Once the coil is clear of ice, you can switch the thermostat back to “cool,” but leave the fan on “high,” not “auto” or “low.”
Coil icing seems to be a more common problem in large diesel motorhomes than other types of RVs. In my opinion, this happens because duct work is so poorly designed that the air conditioner has a harder time moving air than in other types of RVs, but that is just a guess. It can happen in any RV, so the rule of thumb is when the temperature and humidity are both high, the fan should be running on “high” also.
Now for the naysayers: Yes, coil freeze-up can occur with a loss of refrigerant, but it is self-correcting, as a system which loses refrigerant will continue to lose it until the system is empty since it is a pressurized system. That being said, an AC system leaking refrigerant will run with good air delivery but ultimately will not blow cold, so it is easy enough to tell a leaker from a system with a frozen coil.
Stay cool!

Formerly: 2002 30' IB
Re: Air conditioner dripping on inside
Reply #13 –
We've had the same problem since we bought Bossa Nova.  When it is humid or heavily raining, the AC leaks on the inside when the fan is on constantly.  Vince said it was "normal".  It doesn't happen all the time, but aggravating when it does.  To cover ourselves, I lay out a towel underneath the AC unit at night in case it leaks.
David
David and Marie Philbrick
Proud former 2017 27' MB Owners