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Author Topic: Leak or melting ice inside A/C?  (Read 2531 times)

SyrenSkywolf

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Leak or melting ice inside A/C?
« on: December 09, 2013, 04:32:25 PM »
We have been fulltiming for over 2 years now, and are no strangers to locating leaks from our older rv, but this one is interesting, if not annoying. We moved up to a '92 Coachmen a couple months ago. We have never had a leak issue from the roof until now (there is a leak way up at the front window that I am still troubleshooting, but that is a different matter).

Through many good rains, we have never had a roof leak in the few months we have owned this TT. It has been very cold over the last week (in the negatives with single digit highs). This morning, is started snowing heavily. We have gotten a couple inches so far. All of a sudden we noticed a leak from one of the ceiling lights, then progressively to different spots. One of them was the A/C area.

I popped the filter cover off and looked up after spending much time getting bowls under the leaks and inspecting the rest of the TT for leaks. There was ice build-up where the top A/C unit meets the roof. I've had it on fan mode for the past 45 minutes or so to melt it off and dry it out up there. While there are still drips, they are very infrequent now.

The only things different today is the snow, and the fact that we turned the furnace up a bit because we were chilled from being outside (so it maxes out at 75 in here right now, have had it max at 74 to combat the encroaching cold).

I am pretty sure (although not positive) the water was coming from the A/C area, but still not sure if the snow on the roof was causing a pool that leaked in, or the ice build-up inside was melting (assuming it was build-up from moisture). As far as I know it was leaking, and having it turned on to fan is drying out the leak before it travels any further.

Anyone have this issue in the past? If I find it IS a leak, can I patch it for the winter from the inside, or am I going to have to deal with pulling the top unit off this time of year to replace the gasket?

*Picture (quickly thrown together "panorama") shows the order of the leaks when they started. The TT has a slight downhill tilt towards the front, yet the leak discoveries worked their way towards the back. No leak at the ceiling seams at the A/C. Just from the filter, both ceiling lights pictured, and the seam with the numbers.

SyrenSkywolf

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Re: Leak or melting ice inside A/C?
« Reply #1 on: December 09, 2013, 04:36:33 PM »
Forgot to mention I noticed the one accessible bolt wasn't "tight" and I could tighten it another 20 turns or so. After I'm done defrosting/drying it out up there with the fan, I am going to drop the A/C and check the other 3 bolts. Possible culprit? Not sure if tightening that one bolt affected the drop in leaking or not.

Molaker

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Re: Leak or melting ice inside A/C?
« Reply #2 on: December 09, 2013, 05:04:55 PM »
The first time I noticed a leak was water actually filling up a light fixture and then dripping.  It turned out to be the seal between the plastic cover and the metal frame of a nearby roof vent.  The seal was bad and rain would splash up from the roof and get into the inside of the vent.  Then it ran down and onto the top of the ceiling board.  From there it traveled to the nearby light.  I did not change the seal.  Instead, I installed a Camco vent cover on all vents and never had another problem with it.
 
I don't know if that's your problem, but sure sounds like it could be.  If ice builds up around a vent it could allow seepage past the seal.
Tom & Joyce and Ditto the "don't tell her she's a dog" Westie
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Gary RV_Wizard

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Re: Leak or melting ice inside A/C?
« Reply #3 on: December 09, 2013, 06:41:02 PM »
Quite often the leak is nowhere near the place where the water drips out of the ceiling, but your description suggests that at least part of the problem is the a/c itself. My main concern is how did it get cold enough up there to freeze moisture on the inside? That implies more than just a drip - a lot of "cold" is getting in as well. Or perhaps ice is forcing its way underneath the a/c where a seal is damaged.

That loose bolt sounds like at least part of the problem - they need to be snugged up once in awhile - but if ice is already under the roof unit you probably can't get it pulled all the way back down. And you can't horse on those clamping bolts too hard either - they can strip out.
Gary
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Home: Ocala National Forest, FL

SyrenSkywolf

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Re: Leak or melting ice inside A/C?
« Reply #4 on: December 10, 2013, 08:38:49 AM »
I had vent covers on the last RV, but after costs of a new toilet, skirting the TT for the winter, and waiting on selling the older RV, we didn't have the spare cash for them. Now that the other RV sold, I might pick them up and just loose-set them over the vents for the winter, and attach in the spring. They aren't where the leaks are coming from, though.

About the cold, like I said it has been VERY cold here for the past couple weeks. It looks like I need to pick up a new dehumidifier as well. I noticed that it has only been registering 30% humidity the other day (don't know if it just started that, or if it started a week ago). I took it apart, and cleaned it up, and it would register higher humidity when I blew on it after that, but it still said 30% continuously. I found it odd that the humidity could be so low in here. But then the leaking happened.

My assumption at the moment is with it being out of commission, the humidity has been high enough, and cold enough outside, that ice started forming up in the A/C area, then with the snow blanket up top for insulation, it started getting warm enough in there to melt. The leaking completely stopped yesterday evening, so I am figuring that was the issue.

I just need to buy a new dehumidifier now I guess.
« Last Edit: December 10, 2013, 08:41:02 AM by SyrenSkywolf »

Gary RV_Wizard

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Re: Leak or melting ice inside A/C?
« Reply #5 on: December 10, 2013, 02:32:58 PM »
If it is humidity, it apparently condensed & froze only in that one place. Is that the only place where it dropped below freezing inside?  Humidity would condense on every cold surface, which should have been the insides of ALL of the exterior walls (and windows) and the underside of the roof. Yet it froze only there. Why?
Gary
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Gary Brinck
Summers: Black Mountain, NC
Home: Ocala National Forest, FL

SyrenSkywolf

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Re: Leak or melting ice inside A/C?
« Reply #6 on: December 11, 2013, 01:43:29 PM »
A day or two before the leak, we noticed condensation in some of the cupboards, mainly in the bedroom (cooler in there), and condensation on the metal trim of the windows, again mostly in the bedroom (including a few spots of frozen condensation on the trim). The area with ice buildup in the A/C was above the roof line, just above where it meets the metal roof.

SyrenSkywolf

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Re: Leak or melting ice inside A/C?
« Reply #7 on: December 14, 2013, 03:25:59 AM »
Purchased a new dehumidifier a few days ago, and it works better than our other one ever did. No sign of condensation anywhere, including behind the shades in the bedroom, where there has always been at least some dampness on the metal trim.

Even with snow still on the roof, there has been no sign of leaks or wetness. Guess we know the answer now.

The original one was a Danby 30 pint, the new one is a GE 50 pint. The only thing I miss is the Danby was quieter. The low fan setting on the GE is as noisy as the high setting on the Danby :[

John From Detroit

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Re: Leak or melting ice inside A/C?
« Reply #8 on: December 14, 2013, 08:05:16 AM »
Some thoughts on air conditioners... WHEN RUNNING the indoor coils get quite cold and can ice up, MOST rooftop A/C's have a "Frost Sensor" (Thermal sensor) that is stuck into the fins of the indoor coils (MOST = Not all) and this is designed to kill the compressor before ICE builds up.. Still it can happen.

Low Coolant (We say Freon but it's not any more) can cause icing as well.

If it's cold out and warm/moist in,  Condensation happens. As discussed already.. Very rare, but it happens.  INSLUATION may help here.. I can't tell you how to insulate exactly but keep it on the blower housing, not the rest of the A/C.

Finally, IF the AC is operating... On my coach one of the A/Cs drips water off the rear, the other the driver's side, if the rig is low in front (As it was last week but not a problem) or low on the curb side, the "inside" lip of the water tray can be lower than the drip lip and when that happens.. Well you can figure it out I'm sure (it was not a problem last week because.... >Weolll... Did not need the A/Cs.)

And if the air intake filters are dirty... The blower will create a vacuum and it can be enough to SUCK water out of the tray and into the area above the filter.. Took me 8 years to figure that out... And sure enough, it fixed it.

When this happens you hear gurgling when the blower is running and when it stops....

NIAGARA FALLS.
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