Water tank installation

[cheetah1]

I'm trying to install a new Atwood 6 gal water tank by myself, but I've run into a situation that I cannot seem to find an answer for here on the forums or on a Google search. And yes, I am an amateur when it comes to working on our Airstream - but we're trying!

The situation is that this new water heater is going into a smaller opening than the old water heater (the original on our 68 Sovereign) came out of. I had a piece of aluminum cut that I plan on riveting in that area that will reduce the rectangular hole that is there and give me the properly sized opening for this Atwood. The Atwood fits perfectly into the new opening.

What I can't find info on - is what to/how to attach the new Atwood to the trailer from the exterior. Once I use the butyl tape under the exterior flange, do I screw the heater directly into the exterior skin or - should there be a frame behind that skin? Instinct tells me I should somehow build a frame in the interior for the hot water tank flange to get screwed to - but - I can't seem to find any info on that or how to build that frame.

Any insight would be greatly appreciated!

[68 TWind]

I ran into the same situation with my 68. I made a panel out of the proper alloy aluminum with a cutout for the new heater. I used Olympic rivets spaced like originals to attach the panel to the trailer and then used SS screws to attach the water heater to the lip of the new filler panel as the Atwood instructions showed. Once you have all the screw installed, the plumbing and gas line attached it is very secure. PM me if you would like me to send you pics of my Trade Wind.

[rmkrum]

You may have to put a support block at the bottom back edge of the heater to hold the heater weight and keep resulting stress off the skin, but screws through the flange into the skin is how most heaters are mounted. Be sure to use butyl tape or some other stays soft sealant between the flange and skin so you can pull it when it needs replacing. Use Sikaflex to neatly caulk around the screws and flange edge to keep things leak proof (as best as you can). Be gentle hand-tightening the screws, and size the pilot holes properly so they won't pull out or dimple the flange or distort the skin.

My tankless install was into a joke just barely big enough to fit the heater case into the hole. Figured that gives more 'meat' for the screws to go into and more area for the sealant tape to make its seal.


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[rmkrum]

Hole, not joke. I hate autocorrect


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[cheetah1]

Thank you for your response. I too am planning on using Olympic Rivets with the proper spacing to attach the approximately 4" wide panel to the trailer. You mentioned you used SS screws to attach the water heater to the lip/ edge of the new panel. Would you have a recommendation of using self-tapping SS screws vs drilling a pilot hole and using regular SS screws?

Being somewhat new to this forum, please let me know how to PM you. I would like to see the pics of your Tradewind and of this install.

Chester

[cheetah1]

Thank you of the insight. I did have a shallow pan created to place the hot water tank in as it sits on the floor of the trailer. Your suggestion for using a block on the bottom edge of the back of the tank to keep it from shifting backward is an excellent idea!

I have never used Sikaflex, but I have used TremPro 635 extensively in the work we have done so far on this trailer. Do you know of any reason I could not use the TremPro 635 in this application also?

You also mention using pilot holes for the screws. Is there a reason why I should not use self-tapping SS screws in favor of drilling pilot holes and using regular SS screws?

Chester

[rmkrum]

Tempro is also good. The block on mine fills a gap between the floor and bottom of the water heater. I don't use self-drilling SS screws because I can't get them locally. I used regular SS sheet metal screws and put them in one at a time to maintain hole alignment. Tightened them lightly until I got them all in, doing the corners first. Then tightened enough to seat the sealant tape. Cleaned off the excess with s plastic tool and then applied caulk on the edge. It's still well sealed two years and multiple trips later. Put a bright aluminum door on the tankless and it looks like it belongs there...

Go slow and careful and it should be fine. I did have to trim my bottom rub rail to fit my heater, as its door is about 1/2 inch wider than the original Atwood. My old heater is being used to refurb a vintage AS in Canada...


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[cheetah1]

Thank you rmkrum! I feel a lot more confident installing this water heater now. Before the advice from you and 68 TWind, I just couldn't get my mind past just attaching this new water heater with screws just to the aluminum walls of the Airstream rather than to some wood framework support on the interior wall.

I appreciate the advice!

Chester

[rmkrum]

Just go slow, dry fit it several times, and study the plumbing routing. It's not hard to do neatly. I had to make the height of my hole taller twice before it just barely slid in...such is better than the alternatives😄😄😄


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[68 TWind]

RK is correct on a small wedge in the back under the tank to get the door of the heater in line with the outside of the trailer. I forgot about that, it has been several years. If you have cleaco's to hold everything in place use them. They really help in getting things positioned where you want them. Go slowly is good advice. Think every thing through a couple of times before you drill any holes. I did not use self tappig screw just SS sheet metal screws. Also, don't forget to install the corner pieces that come with the heater in each corner of the opening. Good luck. I used Tempro.