| [GMCnet] Leaking Roof AC [message #161904] |
Wed, 29 February 2012 19:52  |
George B.
Messages: 213
Registered: February 2012
Karma: 1
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Senior Member |
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New GMC owner & 1st post!
Last Oct. we attended our 1st GMC rally with the Western States at Emerald
Desert RV in Palm Desert. The temp was in the 100's plus high humidity.
Well our Duo-Therm Penguin roof AC was producing so much condensed water
that it started leaking inside. We had to scramble to find enough pots &
pans to contain the down pour. I found the PO had put at least 2 tubes of
silicone caulk all around the base of the AC & the roof indicating a
previous problem. I peeled off some caulking figuring that it was actually
trapping water inside but it was too difficult to get much off. What little
came off let some water out but it still leaked inside. Needless to say it
interfered with an otherwise great time.
I am now tackling the problem at home (finally). I see that the roof gasket
is fully compressed which is hopefully the root cause. I will clean off the
caulk best I can, try to find where the water is supposed to drain & make
sure it is not blocked and install a new roof gasket.
Has anyone else had a similar problem and how did you correct it? Is there
anything else I should look for?
Thanks
George Butts, KJ6SXA
Apple Valley CA 73 Custom
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George Butts
Las Vegas Nevada
73 "Custom 26' Q" & 76 23' Birchaven
71 Honda 600 Coupe & 01 Tracker Toads
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| Re: [GMCnet] Leaking Roof AC [message #161908 is a reply to message #161904] |
Wed, 29 February 2012 20:25  |
midlf
Messages: 2212
Registered: July 2007
Location: SE Wisc. (Palmyra)
Karma: 1
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Senior Member |
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| GEORGE BUTTS wrote on Wed, 29 February 2012 19:52 |
New GMC owner & 1st post!
I found the PO had put at least 2 tubes of
silicone caulk all around the base of the AC & the roof indicating a
previous problem. I peeled off some caulking figuring that it was actually
trapping water inside but it was too difficult to get much off. What little
came off let some water out but it still leaked inside.
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I can't address your main question but to remove the sillycone caulk try this stuff:
http://www.gmcmhphotos.com/photos/showgallery.php?cat=5214
Steve Southworth
1974 Glacier TZE064V100150 (for workin on)
1975 Transmode TZE365V100394 (parts & spares)
Palmyra WI
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| Re: [GMCnet] Leaking Roof AC [message #161924 is a reply to message #161904] |
Thu, 01 March 2012 00:38 |
sgltrac
Messages: 2797
Registered: April 2011
Karma: 1
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Senior Member |
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The condensation should drain out of the pan which sits on top of the roof and under the unit. I would remove the outer cover and look for the drain holes in the pan and make sure they are not blocked with tree debris or a well misguided p.o.
Sully
77 royale
------Original Message------
From: GEORGE BUTTS
Sender: gmclist-bounces@temp.gmcnet.org
To: gmclist@temp.gmcnet.org
ReplyTo: gmclist@temp.gmcnet.org
Subject: [GMCnet] Leaking Roof AC
Sent: Feb 29, 2012 5:52 PM
New GMC owner & 1st post!
Last Oct. we attended our 1st GMC rally with the Western States at Emerald
Desert RV in Palm Desert. The temp was in the 100's plus high humidity.
Well our Duo-Therm Penguin roof AC was producing so much condensed water
that it started leaking inside. We had to scramble to find enough pots &
pans to contain the down pour. I found the PO had put at least 2 tubes of
silicone caulk all around the base of the AC & the roof indicating a
previous problem. I peeled off some caulking figuring that it was actually
trapping water inside but it was too difficult to get much off. What little
came off let some water out but it still leaked inside. Needless to say it
interfered with an otherwise great time.
I am now tackling the problem at home (finally). I see that the roof gasket
is fully compressed which is hopefully the root cause. I will clean off the
caulk best I can, try to find where the water is supposed to drain & make
sure it is not blocked and install a new roof gasket.
Has anyone else had a similar problem and how did you correct it? Is there
anything else I should look for?
Thanks
George Butts, KJ6SXA
Apple Valley CA 73 Custom
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Sully
77 Royale basket case.
Future motorhome land speed record holder(bucket list)
Seattle, Wa.
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| Re: [GMCnet] Leaking Roof AC [message #162006 is a reply to message #161924] |
Fri, 02 March 2012 02:09 |
Larry C
Messages: 1168
Registered: July 2004
Location: NE Illinois by the Illino...
Karma: 0
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The condensation should drain out of the pan which sits on top of the roof and under the unit. I would remove the outer cover and look for the drain holes in the pan and make sure they are not blocked with tree debris or a well misguided p.o.
I will add to this...
First, the ac sits on a foam donut, 14x14' square. The AC is sitting on top and the pressure from the attachements is what keeps the water out.
On older units, sometimes the drains in the pan can get plugged and the water will build up and eventually find a way inside the coach.
Another problem could be that the pan has a rust hole where the water can leak in.
Another thought that can happen is the donut may become brittle and lose the effectiveness to seal the water out.
When I resealed the SOB roof, the roofers told me if I wanted to guarentee no leaks from the AC donut, the thing to do was to raise the donut from the RV roof by 3/4" with a wood that stands up to moisture well. When I apply the roofing, they said to apply the roof material up the side of the wood and on top so that the donut would sit on it.
This was a fix for water that might get in when driving down the road in a rain at 60 miles an hour but if the water is getting in under the donut, this would have stopped it.
the donuts are available if yours is in trouble. I would apply some sealant around the bottom of the donut and let it seal when you apply the donut, with the sealant toward the roof, onto the roof.. Make sure the roof surface is clean and in good condition. If the pan is rusting but can be fixed you might clean it up and epoxy it. I have seen folks use silicone for such fixes but I have seen silicone come loose in weather or wet conditions. But I have also seen holes in car floors repaired with epoxy and fibre glas cloth, so I know it will work... lol
Good luck with your project.
Gatsbys' CRUISER  08-18-04
74 GLACIER X, 260/455-APC-4 Bagg'r
Remflex Manifold gaskets
CampGrounds needed, Add yours to "PLACES" />
http://www.gmceast.com/travel
_
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| Re: [GMCnet] Leaking Roof AC [message #162022 is a reply to message #161904] |
Fri, 02 March 2012 08:14 |
JohnL455
Messages: 4447
Registered: October 2006
Location: Woodstock, IL
Karma: 12
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Sounds like the PO used way too much silicone in the wrong place. My guess is is back-fed up and closed the drain holes. Wrong stuff in the wrong place.
John Lebetski
Woodstock, IL
77 Eleganza II
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| Re: [GMCnet] Leaking Roof AC [message #162024 is a reply to message #162022] |
Fri, 02 March 2012 08:33 |
Keith V
Messages: 2337
Registered: March 2008
Location: Mounds View,MN
Karma: 0
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Senior Member |
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I have 2 nice new penguins that leaked whenever there was a hard rain. It was all because the MH sits slightly nose down at home in it's parking spot. this means any water will run to the front of the AC pan. Once there it has a large lip to get over.
so the water collects there and runs under the ducting which isn't sealed very well, just open cell foam...
So I added a drain hole in the front and sealed the ducting with some 5200.
Problem solved
Keith Vasilakes
Mounds View. MN
75 ex Royale GMC
ask me about MicroLevel
Cell, 763-732-3419
My427v8@hotmail.com
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| Re: [GMCnet] Leaking Roof AC [message #162121 is a reply to message #161904] |
Sat, 03 March 2012 15:22 |
Erv Troyer
Messages: 125
Registered: February 2004
Location: Lagrange, IN
Karma: 0
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| GEORGE BUTTS wrote on Wed, 29 February 2012 19:52 |
New GMC owner & 1st post!
<snip> The temp was in the 100's plus high humidity. Well our Duo-Therm Penguin roof AC was producing so much condensed water that it started leaking inside. We had to scramble to find enough pots & pans to contain the down pour. I found the PO had put at least 2 tubes of silicone caulk all around the base of the AC & the roof indicating a previous problem. <snip>
George Butts, KJ6SXA
Apple Valley CA 73 Custom
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George, from your description it appears your problem was the sealant that someone added around the base of the unit - this will only trap condensate and cause it to spill into the coach.
You have received several good replies on this problem, but there is one item that wasn't mentioned. I was a Service Engineer for Duo-Therm back at the time our GMCs were being built, and I recall a Service Bulletin I later wrote for the Penguin models, about condensate leakage in high humidity conditions.
In very high humidity conditions the evaporator (cooling) coil will get saturated with water, which in turn will narrow the air opening between the fins, thus increasing the velocity of the air through the coil. This will cause water to be blown off the coil and sucked into the blower, and it will then drip out inside the air box inside the coach. This will only happen when the blower is on HIGH speed, and in very high humidity conditions, and only on the Penguin (low profile) models. Our recommendation in the Service Bulletin was to run the blower on MED or LOW speed until the humidity level had been lowered inside the coach.
This problem occurred a few years ago at the GMC MI rally at Amana, IA. This was a stretch GMC with 2 Penguin air conditioners. When Dick described the problem I said I would check it out for him. I had the top covers removed looking for a broken drain pan, but I could find nothing wrong. Then I started remembering that Bulletin I wrote years ago, so I told Dick to run the AC's on MED until the coach was cooled down - no more problem. Ach, ve get too soon oldt, und too late schmardt!
If you plan on changing the roof gasket I would suggest you put the sticky side down on the roof. In the future you can remove the AC unit without getting the gasket damaged in handling the unit. Duo-Therm wanted to ship these gaskets loose with new units so the installer could attach them to the roof. However, the gasket company could not guarantee the shelf life of the paper-backed adhesive, so we had to attach the gasket to the bottom of the unit.
During installation the gasket should be compressed to about 1/2 its normal thickness, which is about 1 inch.
Hope this info helps
Erv Troyer Lagrange, IN
74 Sequoia
reo43@aol.com
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| Re: [GMCnet] Leaking Roof AC [message #163277 is a reply to message #161904] |
Sat, 17 March 2012 14:27 |
George B.
Messages: 213
Registered: February 2012
Karma: 1
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Senior Member |
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Thanks to all. Steve, Larry, John, Keith, Erv. for all the good information.
I got the AC off the roof and found, in addition to the bad gasket and all
the caulking, that the Styrofoam drain tray that the evaporator sits in had
part of the ends broken off. This allowed the water to leak into the pan
before it even got to the channel to drain holes. I assume the PO tried to
open up the passage with a screwdriver or something and ended up breaking
the Styrofoam.
Steve, seems that Red Devil Caulk Remover you recommended must have worked
so good that the California regulators took it off the market here. I tied
a "New & Easy Safe Green Product" (Motsenbocker's Lift Off) that Lowe's
sells and talk about a waste of time.I ended up having to use my disc sander
to get all of silicone caulk off the roof.
George
------Original Message------
From: GEORGE BUTTS
Sender: <mailto:gmclist-bounces@temp.gmcnet.org>
gmclist-bounces@temp.gmcnet.org
To: <mailto:gmclist@temp.gmcnet.org> gmclist@temp.gmcnet.org
ReplyTo: <mailto:gmclist@temp.gmcnet.org> gmclist@temp.gmcnet.org
Subject: [GMCnet] Leaking Roof AC
Sent: Feb 29, 2012 5:52 PM
New GMC owner & 1st post!
Last Oct. we attended our 1st GMC rally with the Western States at Emerald
Desert RV in Palm Desert. The temp was in the 100's plus high humidity.
Well our Duo-Therm Penguin roof AC was producing so much condensed water
that it started leaking inside. We had to scramble to find enough pots &
pans to contain the down pour. I found the PO had put at least 2 tubes of
silicone caulk all around the base of the AC & the roof indicating a
previous problem. I peeled off some caulking figuring that it was actually
trapping water inside but it was too difficult to get much off. What little
came off let some water out but it still leaked inside. Needless to say it
interfered with an otherwise great time.
I am now tackling the problem at home (finally). I see that the roof gasket
is fully compressed which is hopefully the root cause. I will clean off the
caulk best I can, try to find where the water is supposed to drain & make
sure it is not blocked and install a new roof gasket.
Has anyone else had a similar problem and how did you correct it? Is there
anything else I should look for?
Thanks
George Butts, KJ6SXA
Apple Valley CA 73 Custom
_______________________________________________
GMCnet mailing list
Unsubscribe or Change List Options:
http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
George Butts
Las Vegas Nevada
73 "Custom 26' Q" & 76 23' Birchaven
71 Honda 600 Coupe & 01 Tracker Toads
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| Re: [GMCnet] Leaking Roof AC [message #163292 is a reply to message #163277] |
Sat, 17 March 2012 18:28 |
Larry C
Messages: 1168
Registered: July 2004
Location: NE Illinois by the Illino...
Karma: 0
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Senior Member |
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Glad you were able to find the cause and solution.
Like to see "Happy Campers" out there.
Take care
Gatsbys' CRUISER 08-18-04
74 GLACIER X, 260/455-APC-4 Bagg'r
Remflex Manifold gaskets
CampGrounds needed, Add yours to "PLACES" />
http://www.gmceast.com/travel
_
[Updated on: Sat, 17 March 2012 18:29] Report message to a moderator |
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| Re: [GMCnet] Leaking Roof AC [message #163314 is a reply to message #163277] |
Sat, 17 March 2012 20:33 |
midlf
Messages: 2212
Registered: July 2007
Location: SE Wisc. (Palmyra)
Karma: 1
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Senior Member |
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| GEORGE BUTTS wrote on Sat, 17 March 2012 14:27 |
Thanks to all. Steve, Larry, John, Keith, Erv. for all the good information.
Steve, seems that Red Devil Caulk Remover you recommended must have worked
so good that the California regulators took it off the market here.
George
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Geez I'll have to check here. I hope it was a Kalifornia thing and not an EPA thing.
Steve Southworth
1974 Glacier TZE064V100150 (for workin on)
1975 Transmode TZE365V100394 (parts & spares)
Palmyra WI
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