I’m looking for confirmation concerning my motorhomes AC. My RV is a 1994 33’ Holiday Rambler Vacationer. I bought it as a fixer-upper and am in the home stretch right now for moving into it full-time. The summer Texas heat has finally arrived so the other day I turned on the AC. After about 15 minutes I went outside looking to see where the condensed moisture was draining from the AC, there was nothing, yet it was a very humid day. Suddenly water started running off the roof-top and spilling down the side of my MH. I was expecting there to be some type of between-the-walls piping to funnel the AC water under the MH. I discussed this with the parts guy at my local Holiday Rambler dealer and he said that there was no piping, that the system was designed to empty out onto the roof just like mine was doing. This is very disappointing news, I have visions of green scum growing down the side of my MH by mid-summer. Am I missing something here, or is that really the way that these things are designed?Steve

99.9% of all roof top AC units simply drain the condensation onto the roof. So what you are experiencing is normal. I have never seen green scum or anything else.

Steve,Yes this is perfectly normal for the a/c to drain off. We had a new Discovery DP that did the same thing as well as many other TTs and motor homes. That is just how they are designed.Vic

At the age of your coach, you want to watch out for AC condensate drain water coming into your coach from a bad gasket on the roof. Sometimes the gasket hardens and collapses somewhat and you have to take a few turns on the AC mounting bolts to tighten things up again. DO NOT over tighten the AC bolts, just snug them down on the gasket.

You don't want any kind of opening into the walls for water to run down. Even if it is a tube. I could spring a leak inside the wall and you don't want that.Watch others a/c.

I would also go up top and look if the condensation is pooling on the roof. I've seen many where the heavy ac and an older roof leaves the ac sitting just a bit lower than the roof line and the water can not go anywhere and that's where you will see green moldy standing water. Unlevel the MH so it can exit the roof.My first time in humid Florida a mobile RV repair guy said that since we are so focused on having our RV's perfectly level, and more gadgets to get it perfectly level, that he see's more and more standing green water on tops of RV roof's from the ac unit because it doesn't drip off the edge enough. Drainage also depends on the amount of humidity and how hot the sun. Sometimes there is not a lot of condensation and the sun is hot enough to dry it out before it gets to drip. He advises that if you see it not dripping consistently during a hot day to tip the MH a smidge to make sure it gets off the roof.I do that now and I see a difference how much more comes off the roof.

Should my AC empty condensor water to the roof?

17 Replies

RoyB
Explorer II
May 29, 2013
My air conditoner drains directly on the roof of my trailer and runs toward a side mounted drain gutter which routes the water to one end of the trailer or the other. I always angle my trailer abit toward the back when I setup to make the water flow to the back of the trailer.

This is pictorial of the roof mounted air conditioner. Note the 14" x 14" foam gasket sandwiched between the air conditioner housing and the trailer roof. This gasket is what keeps the roof water from coming inside your trailer. This gasket should be depressed about a 1/4-inch by tightening four long bolts from the bottom side of the air conditioner mount accessible from the inside unit.

I have seen some folks apply some dicor on the roof to make a dam of some sort to direct the water flow of the air conditioner directly to the side drain gutters. They also apply some dicor on the rear of the roof to keep water from running down from the roof onto the rear big picture windows.

just my thoughs
Roy Ken
Peralko
Explorer
May 29, 2013
Not all motorhomes drain onto the roof. While our 91 Pace Arrow did, our present coach has drain tubes that are routed through the walls.
DSDP_Don
Explorer
May 29, 2013
Some of your higher end coaches had drain tubes, but as one poster stated, most don't. There was a company that made a pan that could be placed under your A/C unit and included a drain tube you could route along your roof to the side of the coach. The downside is you have to remove the A/C units to install the pan.
time2roll
Nomad
May 29, 2013
Why does that pic look like the water would drain into a hole in the roof?
dkreuzen
Explorer
May 29, 2013
I was pleasantly surprised when I found out my new Monaco had drain tubes from each A/C unit that were routed to the rear of the coach. No more draining down the sides.
2bzy2c
Explorer II
May 29, 2013
Geocritter wrote:
This isn’t the news I was hoping for, however the roof on my HR is slightly rounded so at least it doesn’t puddle on top. The other day I climbed up and took off the shroud. The photo is of the discharge hole for the water.

I’m thinking I can fabricate a small thin plastic catch-tray to slide between the shell and the roof under the hole. Then run a tube from the tray off past the edge of the roof. This would be a temporary setup and used primarily at month or longer stops.

Steve

Just because most RV's just let the water run off of the roof, does not mean you can't improve it.

I like your idea of routing the water down a tube.
rockhillmanor
Explorer II
May 29, 2013
ALL RV's drip off the roof.
Some of the newer more costly ones have intricate systems for it.

Why do you want to make more work for yourself than you have to by putting an attached tube on and off when ac condensation dripping off the roof is acceptable and the way it is designed to function?
Geocritter
Explorer
May 29, 2013
This isn’t the news I was hoping for, however the roof on my HR is slightly rounded so at least it doesn’t puddle on top. The other day I climbed up and took off the shroud. The photo is of the discharge hole for the water.

I’m thinking I can fabricate a small thin plastic catch-tray to slide between the shell and the roof under the hole. Then run a tube from the tray off past the edge of the roof. This would be a temporary setup and used primarily at month or longer stops.

Steve
time2roll
Nomad
May 29, 2013
Normal. When there is a problem it apparently drips inside the RV as many posts indicate.

Maybe some RV rain gutters are in order to redirect the water.
carp65
Explorer
May 29, 2013
We have small rain gutters on both sides of our 2005 GeorgieBoy. Water from
front runs to the passenger side front and the rear to the passenger side rear.
It handles both rain water and condensation water from the air conditioners