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mlh2013 · 07-20-2015, 04:25 PM

I have a 99 dip with Duo Therm roof air and the one in the bedroom keeps leaking water inside the motorhome. I have tightened the bolts about as tight as I can helped some but still leaks. I think I may need to replace gasket. Can anyone tell me just how to do this.

Old Scout · 07-20-2015, 04:43 PM

Its a modest pain and a two person job--first, I think the spec on the hold-down bolts is like 50 or 60 INCH pounds so overtightening can be an issue. Second, lots of wires so to avoid disconnecting everything, remove 4 hold-down bolts and tip unit on side. If you have ducted air vents, you need to disconnect the ductwork on the bottom of the unit. Third, buy the grey, not the white [more dense/more expensive] 14" gasket[s][if you have drain cups, it takes two gaskets per unit[may need to disconnect drain lines for slack]. Fourth, separate gasket at corner so you can get it around wiring. Fifth, use some light sealant for corner and bottom of gasket that contacts RV roof [instruction say no but I recommend it] Sixth, replace unit, and center--unit is cantilevered off the back of gasket so recommend rigid foam blocks under back of unit frame to level/balance weight. Seventh, re-install, tignten bolts to 50-60 INCH lbs.

mlh2013 · 07-21-2015, 08:34 PM

Thanks Old Scout, got the gasket today gonna give it a try.

walt2137 · 07-22-2015, 07:38 AM

MLH one of the biggest problems with leaking roof air gasket is the hold down bolts vibrating loose I use a dab of blue loctite on my bolts and tighten as old Scout said only I was told by a Duo therm tec to loosen the nuts all the way off let the gasket seal relax for a few hrs then tighten to 40 to 45 inch lb but either would work the main thing is don't over tighten

mlh2013 · 07-23-2015, 11:59 AM

Thanks Walt, got it replaced yesterday. I ran it for several hrs. with no problems, It wasn't as bad as I thought, I changed it out by myself. Thanks for your help guys.

mlh2013 · 08-01-2015, 07:49 PM

well went to Nashville ran air and the leak started again. could there be a drip pan somewhere that could be causing the problem

walt2137 · 08-02-2015, 07:56 AM

The 99 dip does not have a drip pan, the AC could be low on coolant and freezing up then melting and dripping inside the coach, pull all the grill from the inside turn it on and see if that's the leak.

RustyTools · 08-02-2015, 05:00 PM

Could the roof itself be drooping in the middle (because of the weight of the A/C), and cause a puddle to form on the outside and allow seepage to dribble in?

Not being familiar with that model/vintage, so I'm also going to ask how the condensate is channeled away from the coils and off the roof. Could there be a blockage or restriction causing it to back up?

walt2137 · 08-02-2015, 05:12 PM

On the Monaco Diplomat it does not have a drain system other than it just runs out of the AC on the roof, I guess the drain hole could be plugged the best I rember it a pretty big hole.

RustyTools · 08-02-2015, 05:56 PM

That's what I was thinking too, Walt. It's like my Endeavor/Diplomat. My drain holes (one on each side) out of the A/C frame have gotten clogged before with pine needles.

And, yeah, the holes are big enough to stick a little finger up/in them. Hopefully something as simple as that.

bruceisla · 08-02-2015, 06:21 PM

Quote:

Originally Posted by mlh2013

well went to Nashville ran air and the leak started again. could there be a drip pan somewhere that could be causing the problem

You haven't mentioned whether the leak is from rain or condensation.

If it's condensation you probably have failed tape between the warm side and the cold side. You can look at this from the inside. Pull the inside cover plate (like you did to replace the gasket) and look for any loose or missing metal tape. Bad tape causes the cold side to bleed cold air to the warm intake side which causes frost to build on the evaporator. It's common in older RVs. The tape is "iffy" at 10 years or older.

mlh2013 · 08-04-2015, 11:47 AM

Sorry I have been a little bus and haven't had a chance to look at it. But I can tell you that the leak is not from the rain. The tape you are talking about is it the shiny silver looking stuff.

bruceisla · 08-04-2015, 05:16 PM

Quote:

Originally Posted by mlh2013

Sorry I have been a little bus and haven't had a chance to look at it. But I can tell you that the leak is not from the rain. The tape you are talking about is it the shiny silver looking stuff.

Yes.