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

MustangGT
Explorer
May 29, 2013
My a/c's condensate usually drips off the gutter extender outside the driver's side window after it leaves the roof. Doesn't hurt anything. That is a way better design on most lower cost units than having any water pipe running unnecessarily inside a thin wall panel.
I have found some green slime to the rear of each A/c unit as this area rarely sees direct sun during storage. It is easy to clean-up or just let the heat dry and evaporate it.
kaz442
Explorer
May 28, 2013
My roof pools when I have it level. I always forget when Im taking it off the blocks to leave to close my windows. Never fails I take a shower!! At least I know the roof don't leak!!

I belive the newer MH have a crownd roof to prevent it from pooling.

JKaz
rockhillmanor
Explorer II
May 28, 2013
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.
daverich
Explorer
May 28, 2013
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.
rgatijnet1
Explorer III
May 28, 2013
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.
trickyvic3
Explorer
May 28, 2013
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
wildtoad
Explorer II
May 28, 2013
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.

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Should my AC empty condensor water to the roof?

17 Replies

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