AC replacing gaskets

[jacwjames]

My AC units are original and still work but I have had occasional leaks.  I have periodically tightened the 4 bolts that hold the AC units down but I think I need to replace the gaskets as they are all original and I have no doubt they are compressed. 

My AC unit is 630515.321E1

The gasket number shown in the parts breakdown is 3100247.000, these are available for $33

I have the condensate drain cups and tubing but my parts list does not show this but I did find a posting saying it is 3107688.016, which has the 2 cups, and tubing plus gasket and spacer.    I am not sure of the condition of the cups, I know previously I'd observed that the lip on at least one of them is cracked.  Has anyone had to replace these.  I guess I could purchase and return if I don't use but looking for advise.   The kits are available for $73.

I assume that I will need add another gasket to account for the tubing.  Do they make an all in one kit that has 2 gaskets, 2 cups/tubing, and spacer.  Buying everything piece meal is $105 per AC unit.  Yikes  Anyone know of a good source/pricing. 

 

[monacowner]

Hey Jim,

 

Before you start replacing things, you might want to dicor the inside of your AC. I know that sounds strange, but water was entering my coach by splashing up under the shroud and into the AC unit, then slipping between a seam in the sheet metal that had no silicone or dicor. I hit that area with a lot of dicor and that solved the problem.

The previous owner was unable to figure that out as the nice fabric-covered vent cover had water stains and even mold. Not good for resale, that's for sure.

[jacwjames]

In E TN so were getting remanents of the hurricane as I type.  Once it stops raining I'll pull the shroud and take a good look.

But the gaskets are all original so it's probably time.  I had a problem with the back leaking but this time it was the front.  I did check the 4 bolts, they were very loose, I used a short crescent wrench and tightened them up.  I have a inch/pound torque wrench but with it raining I didn't want to unload the bottom compartment where it is.

[wamcneil]

Do you have a ducted setup with vents in the ceiling? If that’s the case I’m not sure the bolts should ever be tightened. 
My duct stubs are set up for 1/2” of duct compression. That’s starting with 2 stacked 1” gaskets, and results in the A/C pan being 1-1/2” above the roof. If you crank it on down, it’ll smash the duct down with it. 
Even if your bolts are loose, there’s still the weight of the unit pressing them down on the roof as you crank the bolts down. 
Are you positive that the water is coming in through the gasket? If so, I’d probably try and lift the unit up and put sealant under the gasket. But, those gaskets get fused to the roof like you wouldn’t believe. And they are not exposed to sunlight, so it’s not like they get brittle and crumbled. So I’d look really hard and make 100% certain it’s truly the gaskets before replacing them. 
 

Cheers

Walter

[jacwjames]

Yes, I have the ducted AC .

The water is coming in at the front corner of the AC, not really sure yet why, it's been raining so I haven't had a chance to do anything.  I have only moved my coach a handful of time over the last 3 years (building a new house).  I had it parked off to the side over a 3 month period while I was getting ready to pour a concrete slab for a garage.  It had rained numerous times during that period of times and never did leak.  

Last week I moved it onto the slab so it was sitting about as level as you could get.  After it rained it started to leak, and I don't mean an occassional drip, it leaked a lot.  I did use one of the rear jacks to tip the RV to the drivers side.  Haven't checked it this AM so see the results. 

Either way, I am hesitant to check the gasket without having new ones on hand.  If I'm going to fix it I'm going to do it right. Just looking for advice.

[Moonwink]

My a/c allowed water to pour in when parked at the curb with the passenger side lower than the driver's side.  I replaced the gasket and found a telephone wire (like the ones going into a house) wrapped around the bolts.  When I bought the new gasket, I was told to compress it to half of its uncompressed height.

[Paul J A]

Below is an F Y I C&P post from irv2. This is just intended to provide some past history from other RV folks, NOT a recommendation. Note the torque is in INCH POUNDS.

Here's a piece of the installation manual for the Duotherm Briskair AC unit.

EVENLY TIGHTEN MOUNTING BOLTS TO A
TORQUE OF 40 TO 50 INCH POUNDS.
This will compress the roof gasket to approximately
1/2". The bolts are self locking so over tightening is
not necessary.

Here's another piece of information from a Duotherm Sunchaser rotary XL and Classic series

Evenly tighten the four (4) anchor bolt nuts (D) to
secure the unit and insure a proper roof seal. Since
these nuts have lock washers, do not over tighten,
75 in. Ibs. or 6 1/4 ft. Ibs. torque is recommended.

Proper installation should preclude caulking.
 

[jacwjames]

I checked the motorhome a little while ago, no water came in overnight even though we had lots of rain with some pretty hard down pours. It is tilting slightly to passenger side. 

I will probably order at least one of the replacement condensate cup/gasket kits and a couple new gaskets and take a look at it in the very near future.  I'll let everyone know what I find. 

 

FWIW, I had replaced my carpet in early 2009 with a laminate.  It was a snaplock type but for a measure of safety I used a waterproof glue on the joints.  Over the years the laminate has gotten a workout, especially when my wife would have to take the dogs out for walks in the pouring rain.  We'd put towels down but the flooring still saw a decent measure of water and dirt.  The water coming in the front AC puddled on the laminate and I wiped if off when I found it.  So far it doesn't appear to have hurt the flooring (fingers crossed).  I guess if I had to replace over again I go with the moisture resistant type laminate. 

[miacasa_2000]

I had a crack in the cover that when the wind blew the rain just right would allow water inside the gasket area and drip down thru my filter area.

[Dr4Film]

Wow, $73 dollars for the Drain Cup Kit now. I payed $58 each back in the fall of 2018 when I replaced both AC's. How times have changed!

Good luck with the change-out.

[Guest Ray Davis]

On 10/10/2020 at 10:30 AM, jacwjames said:

I assume that I will need add another gasket to account for the tubing.  Do they make an all in one kit that has 2 gaskets, 2 cups/tubing, and spacer.  Buying everything piece meal is $105 per AC unit.  Yikes  Anyone know of a good source/pricing. 

 

 Jim , I'm rather late to the discussion but thought perhaps I could help .

 The kit comes with the necessary gaskets and pans .   Here is a place I found by googling 3107688.016 auxiliary drain pan kit

 https://pantherrvproducts.com/dometic-3107688-016-auxiliary-drain-pan-kit/      $61.79   probably plus shipping .

 I would go ahead and replace the plastic pans           

[wamcneil]

20 minutes ago, Ray Davis said:

 The kit comes with the necessary gaskets and pans .   

Just for clarity... The drain kit comes with ONE of the necessary gaskets. Use of the drain kit requires TWO stacked gaskets. The other square gaskets are available a-la-carte

[Guest Ray Davis]

Walter is correct , thanks Walter , but his A/C came with a gasket , mine did not go figure .  The kit assumes you will already have 1 gasket .

I think they robbed mine of the gasket probably to sell or use elsewhere .

Anyway I did buy an additional gasket ,  I think I paid about $14 

[wamcneil]

On 10/12/2020 at 6:53 AM, miacasa_2000 said:

I had a crack in the cover that when the wind blew the rain just right would allow water inside the gasket area and drip down thru my filter area.

Unless you can SEE the water seeping in under the gasket, I'd be looking for something like this. My gasket was thoroughly fused to the fiberglass and I've read other posts indicating that that's just what happens. So while I don't have much practical experience with rooftop ACs, it seems to me like these seals wouldn't be a likely source of water intrusion. And if water is coming in the gasket, it should be easy to observe.

The gaskets are pretty soft and most of the weight of the AC unit bearing down on it. It really shouldn't need the bolt pressure clamping it down in order to seal.

In the default installation without the drain pans, the gasket starts off 1" thick, and there are some hard foam blocks about 3/4" thick at the corners of the base pan. Apparently the intention is to compress the gasket ~1/4" and pull the unit down onto the harder foam blocks.

But in the drain pan installation, you've got 2x1" gaskets and they give you a couple additional strips of soft gasket to prop up the back of the unit. In this installation, the hard-foam corner-blocks don't contact the roof, so the unit is being supported by the soft double-stacked gaskets and they will happily compress right on down till the drain pans hit the roof.

That's how mine are. Apparently they'd been re-tightened periodically and the unit pulled right down till it's resting on the drain pans. This would likely leave the rear of the unit sitting up higher than the font and that might allow water entering the base-pan to run forward where it can find its way into the front and then down the intake area. 

Over-compressing the gasket could also cause the drain hose(s) to get pinched. I had this happen with my new unit and only 1/2" of compression. This caused one of the drain cups to overflow onto the roof when the coach is tilted toward the one side that was obstructed. If your drains are pinched from over-compression, maybe the incoming rain is overwhelming the cups and making its way into your intake duct.

Cheers,

Walter

[jacwjames]

Walter M

I could not specifically see where the water was coming in from but it was running down the inside of the frame cut out the AC unit above. 

I think the only way I'll know what's going on is to pull the AC units up and inspect to see if there are any tell tale signs where the water came from.  If I do that I might as well and be prepared to replace the gaskets.  I found a source that sells both the gasket kit and drain pan kit so I am going to buy 2 sets of gaskets and drain pans just in case.  They won't go to waste as eventually my luck will run out and I'll have to replace the AC units.   

Here is the website that had the best price the drain pan kits.  https://www.rvautoparts.com/search

If I buy it all the shipping will be offset. 

Edited my Jim J

After processing my order they infomred me that they do not have any drain kits in stock so I will just get gaskets for the time being.  Why companies will process an order and then inform you they don't have stock of an item I'll never know. 

I ended up ordering 2 drain pan kits from Panther RV, decent price on the item but the shipping was $25, cheapest shipping was FedEX

 

Edited October 14, 2020 by jacwjames

[jacwjames]

It must have been a Monday when they installed my roof AC's.  Since I have the drain pan type design installation required 2 gaskets. 

When I removed both AC units the gaskets were not mated correctly.  Attached are pictures.  The rear unit the gasket next to the passenger side drain pan was completely missing the first gasket, which was the location that I leaks, tightening the bolts did not fully compress the gasket.  On the front AC unit the gasket on the front was completely misaligned, the day that I had a leak we had a storm from that direction and I'd say the wind pushed the water up over the gasket.

Overall the job wasn't too bad.  On the rear AC I put wire caps on the wires sending 12 volt to the unit but didn't cap the wires coming from the unit.  When I was reinstalling the AC one of the 12 volt wires hit the foil covered duct and arched, I crapped my pants and then realized it was the power coming from the capacitors.  Didn't make that mistake on the second one. 

I also found that the rear AC unit ducting was not sealed completely and that it appeared when the installed the AC unit the slip duct that is use to mate to the roof ducting actually crushed a portion of the roof ducting.  From appearance a lot to the cooled air was recirculated right back to the air intake. 

I also found that the gaskets took multiple series of tightening to get them compresses.  I used the slip duct as a guide as to how much to compress and a cordless drill with adjustable torque to pull the AC units down evenly. 

Overall not a bad job.  Working by myself it took a total of 6 hours.

[Guest Ray Davis]

 Jim,  Thanks for the pictures.    I have an 03 Windsor and my air conditioners don't have that slip duct , I remember Walter posting pictures with a slip duct too.

 When Walter posted his pictures I thought it was interesting the difference in models, now I wondering if I'm missing something.   Mine seems to work ok but I

 really don't have anything to compare it with.     I'm wondering does everyone else have a slip duct system?   

 What I do have that I don't see in your pictures is a sheet metal wall separating incoming air from outgoing air.

[jacwjames]

The slip duct is essentially keeping the cold air and return air separate. 

When I first looked at my AC unit I didn't see that it was actually a slip duct, only after I pulled on it when it was laying on it's top did it move.  If the AC is pulled down all the way it may be that the 2 pieces are fully compressed and not recognizable as a slip duct. 

 

Edited November 22, 2020 by jacwjames

[Dr4Film]

The slip duct is simply two pieces of duct work that nest together and will auto-adjust depending on whether one or two gaskets are used and how much the gaskets are compressed. One side attaches to the bottom of the AC and the other is attached to the actual long foil wrapped duct that traverses the coach.

My coach has them.

[jacwjames]

As an afterthought I would also suggest that owners, if they have ever tightened the 4 hold down bolts should go ahead and check the connection since when you pull the AC unit down you are moving the slip duct and may break the foil tape that seals it to the duct work.

I think on the original install you are suppose to place the AC down with one piece of the slip duct attached to the AC unit, once positioned you then cut through the duct work and cut an opening just large enough to installed the second piece.  Once the two pieces are mated together and the AC unit is pulled down you use foil tape to seal up the two pieces and also to the duct work, this would make for a good seal.

It was obvious on mine that the installers cut a larger opening in the duct work first and then put the AC unit down with both pieces already together.  They actually had to add a couple pieces of duct back to fill the larger void. This resulted in the need for more foil tape to seal everything up. 

It would make sense to check, just use a utility knife to cut the duct work on 3 sides and fold down the piece to access the inside of the duct and check the slip duct.  You should be able to see where it was done before and just cut in the same place.  Use foil tape to seal up any holes and to seal up the duct.  Sealing up a small hole would improve the cooling efficiency quite a bit.  In my case I'm sure I had a substantial amount of short circulating cold air on the rear AC unit.

Edited November 22, 2020 by jacwjames

[Guest Ray Davis]

 Jim and Richard ,  you both have the same slip duct, but I'm sure I don't .  I could not have missed it when I replaced both air conditioners .

 Can you guys see the duct when changing filters?  I wouldn't be able to see it since the wall I mentioned is right there separating in & out air.

 In Jim's pictures it looks like I might be seeing where you had that same wall,   just a faint change of color across the edge of the intake opening.       If I removed the wall the air would just come out and go right back in.

 On mine the air just dumps out into the area where the coach duct openings are on each side, that's it,  if there are any other openings the air can escape into those places.

 I'll not worry about it since it seems to work without the slip duct although yours is without a doubt a better setup 

Edited November 22, 2020 by Ray Davis

[Dr4Film]

The AC duct work runs the length of the coach. It is one continuous rectangle duct with output openings in the bedroom, bathroom, kitchen and salon. There are two inputs where each AC sits on top of the coach and duct work. The return air goes through the filter on each AC and back up to be re-cooled then redistributed once again.

I have attached a Dometic document that shows the top and bottom of the Penguin II AC. The return is the large rectangle opening at the front bottom of the AC. The input is the small square opening just in back of the return opening.

When removing the filter all you see is the large rectangle duct work running the length of the coach and wires. The return is hidden by the duct work.

Edited November 22, 2020 by Dr4Film

[Guest Ray Davis]

Richard,  I think our coaches ducts are identical the difference I'm speaking about is just right there where the a/c unit interfaces with the coach.

This picture that Walter posted some time ago shows what I don't have.  I don't have any of what is in the picture, if I took a picture from that angle of mine

you would see a hole where air goes into the main duct on that side, same thing on the other side

[jacwjames]

The picture is basically what I have although a slightly different design. 

They must have created a different type of transition duct for your coach, which may be better.  If the inlet hole into the ducting was larger it would probably provide for more/better air flow.  The the separation was of a better design possible less likely chance of leaks and recirculating air.  There may also be a less likely chance of crushing the duct work as shown in the picture, which is similar to what happened to mine.

 

 

[Dr4Film]

Ray, if you don't have the sheet metal between the bottom of the AC and the top of the rectangle duct then what contains the cold air to get it into the duct? It would not be very efficient without something in between.

Edited November 22, 2020 by Dr4Film