condensation around AC vents

[Rndygit]

I don't know if this is a common problem or not but last summer was my 1st experience in RVing and I had a terrible problem with condensation around the interior ac vents. It was pretty severe at times and has discolored the headliner in places. I'm raring to go again but would like to know if this is usual or is there a solution to the problem before I venture out again

 

[DearMissMermaid]

Sounds like a roof leak around the overhead AC unit which puts out water when in use.

I keep a big roll of Eternabond  roof tape

http://www.amazon.com/gp/product/B002RSIK4G/ref=as_li_ss_tl?ie=UTF8&camp=1789&creative=390957&creativeASIN=B002RSIK4G&linkCode=as2&tag=recreationalvehicles-20

around and slap it on anything that looks the least bit suspect on my roof. Roof leaks are like a hole in your boat at sea, both can sink you.

 

[John From Detroit]

Sounds to me like high humidity, The air outlets are colder than the rest of the ceiling due to the cold air coming out of them so when the A/C shuts off how warm MOIST air inside the house contacts the cold plastic and condensation happens.

Solution: Fan on HIGH, not auto

 

[Rndygit]

Thanks John I will try that. It happens on every vent...all 7 so I don't believe it's a roof leak. I just put a new coating on the roof after having a leak around the shower skylight so if it was that it should be resovled....and lots of caulking.

 

[Gary RV_Wizard]

If it truly is condensation on the ceiling, the interior humid air around the ceiling ducts is being chilled, which causes condensation. This sometimes happens in a high humidity climate simply from air that enters the interior whenever the outside door is opened.  However, a possible scenario is that condensation is taking place on the metal ducts in the ceiling and dripping out around the outlets. This can mean there is extra moisture above the ceiling (from a roof leak). Even after the leak is fixed, the residual moisture can cause problems for months.