Over the winter of 2021/2022, I was restoring a Sunline 2007 T89SR camper that needed a new water heater, and finding a new drop-in like-for-like water heater, created a few challenges. First off, a little background. Almost all the Sunlines back into the 70s came with an Atwood water heater.
Atwood Mobile sold part of the business to Dometic in 2014. By 2017 Atwood products were being sold under the Dometic brand. https://www.dometic.com/en-us/outdoor/lp/rebranded-atwood
Since Covid started in early 2020 and its share of RV part supply problems, combined with when Dometic discontinued building the last Atwood design water heater as a complete water heater, getting a new water heater has been a challenge. Parts are still available for many Atwood models now made under the Dometic brand. And some of the older Atwood parts have fallen into the discontinued situation.
Finding a completely new Atwood water heater was nearly nonexistent from early to mid-year 2021 to fall 2022. Only dealers with older left-over stock had any, and it was hard to find them. Things started to break free in late 2021 when the new Dometic redesigned heater became available. Anyone with a Sunline camper, this post may help you the day you need to do a total water heater replacement.
In Dec. 2021 and Jan 2022, I bought two new Dometic WH-6GEA water heaters (6 gal, combo gas, and electric), one to install and another to have a spare on hand for one of my project campers. The pricing was nuts, pending where you were looking to buy. The cost ranged from $350 to over $800 on sale, and at some places, close to $1,000 for the same water heater. I was fortunate to find the first one at the $350 price and the second two months later for $365 at a retailer on Amazon. I can't find that price anywhere now that inflation has gone up. It appears $450 is the lowest current price at this post's time, but some retailers still offer them at $800.
Here is a link to the three water heaters offered by Dometic as of this post. It shows all the discontinued models also. https://www.dometic.com/en-us/outdoor/search?q=water+heaters&sortBy=Relevance&count=48
I'll do the rest of this post mainly in pictures, as seeing this change out is where the most help can come in. Here are some overall pics of the new first generation WH-6GEA bought in Dec. 2021. Some parts since have changed, and more on this later.
For comparison, here is the last vintage of the Atwood combo gas & electric water heater used in some of the later 2004 to 2007 model Sunlines.
Here is the new Dometic water heater placed inside the opening of the old Atwood.
The old Atwood opening in the side of a 2007 T289SR
Below is a picture of the new Dometic in the camper opening as a test fit. Thankfully, the heater fits the height of the camper opening, but we have to space in the sides.
They sell a door kit that will convert the new style heater into a retrofit older opening. It is called "Dometic 94016 6 Gallon Water Heater Door Conversion Kit #34 18"W x 14-3/4" White." I bought mine here, which is in Ohio and about an hour away. I get free shipping; not sure if they do it for all outside of OH. The cost of this kit is all over also https://www.boatandrvaccessories.co...lon-water-heater-door-conversion-kit-34-white
You get an oversized door to mimic the original Atwood and two side filler plates. They sell a standard smaller door for new camper installs.
I cut down a 2 x 4 to fit equally on both sides to create the correct opening and screwed them in place flush with the outside wood framing. Note: You must include the thickness of the retrofit side plates when cutting the boards to close in the opening.
The side panel filler plates. NOTE: The picture below shows four screws in these panels. I created lineup holes to ensure these plates return the same way once all the butyl tape etc., is in place. If these plates shift position up or down in relation to each other, the heater will not fit in the hole correctly. The door hinge holes must align with the side plates and the heater flange.
NOTE 2: Due to the mounting location of the T289SR, the top of the heater mounting flange runs into a high ridge bump in the siding. This large bump does not let the heater set flush to the frame wood. I used a large C clamp and 2 x 4 to flatten the large siding bumps flat. Then the heater will be set flush with the wood frame. The old Atwood did not matter as much, as there were no side filler plates. If your floor plan has the water heater pass through this large set of siding ribs, I suggest you flatten them.
Next was to deal with the water piping changes needed. Dometic flipped the inlet and discharge from being stacked to being side by side and from female thread sockets in the tank to male threads on a pipe that hangs out beyond the tank. On a new camper, this is not a problem; on a retrofit, it can create some piping opportunities to overcome. Each camper floor plan may have different issues to work through when dealing with the piping tie back into the existing camper piping. The newer Sunline campers often have a deeper cabinet where the water heater is so I could accommodate the added depth. However, tying into the existing hot and cold piping created a few revisions to get it correct.
Here is the first version. I thought this looked good outside the camper, and I'm using the two-valve heater bypass setup instead of the one 3-way valve and check valve of the older version.
While it looked nice and neat, the hookup inside the camper was not good; it would not work. Here is version 2; it did not work either… a bummer.
So here is the "third" version that did work. Yeh! This piping should be self-draining into the tank, not creating a natural water trap. The water needs to drain back into the heater, not stagnating when not used, the camper drained, and to help with winterization.
More in the next reply.
Atwood Mobile sold part of the business to Dometic in 2014. By 2017 Atwood products were being sold under the Dometic brand. https://www.dometic.com/en-us/outdoor/lp/rebranded-atwood
Since Covid started in early 2020 and its share of RV part supply problems, combined with when Dometic discontinued building the last Atwood design water heater as a complete water heater, getting a new water heater has been a challenge. Parts are still available for many Atwood models now made under the Dometic brand. And some of the older Atwood parts have fallen into the discontinued situation.
Finding a completely new Atwood water heater was nearly nonexistent from early to mid-year 2021 to fall 2022. Only dealers with older left-over stock had any, and it was hard to find them. Things started to break free in late 2021 when the new Dometic redesigned heater became available. Anyone with a Sunline camper, this post may help you the day you need to do a total water heater replacement.
In Dec. 2021 and Jan 2022, I bought two new Dometic WH-6GEA water heaters (6 gal, combo gas, and electric), one to install and another to have a spare on hand for one of my project campers. The pricing was nuts, pending where you were looking to buy. The cost ranged from $350 to over $800 on sale, and at some places, close to $1,000 for the same water heater. I was fortunate to find the first one at the $350 price and the second two months later for $365 at a retailer on Amazon. I can't find that price anywhere now that inflation has gone up. It appears $450 is the lowest current price at this post's time, but some retailers still offer them at $800.
Here is a link to the three water heaters offered by Dometic as of this post. It shows all the discontinued models also. https://www.dometic.com/en-us/outdoor/search?q=water+heaters&sortBy=Relevance&count=48
I'll do the rest of this post mainly in pictures, as seeing this change out is where the most help can come in. Here are some overall pics of the new first generation WH-6GEA bought in Dec. 2021. Some parts since have changed, and more on this later.
For comparison, here is the last vintage of the Atwood combo gas & electric water heater used in some of the later 2004 to 2007 model Sunlines.
Here is the new Dometic water heater placed inside the opening of the old Atwood.
The old Atwood opening in the side of a 2007 T289SR
Below is a picture of the new Dometic in the camper opening as a test fit. Thankfully, the heater fits the height of the camper opening, but we have to space in the sides.
They sell a door kit that will convert the new style heater into a retrofit older opening. It is called "Dometic 94016 6 Gallon Water Heater Door Conversion Kit #34 18"W x 14-3/4" White." I bought mine here, which is in Ohio and about an hour away. I get free shipping; not sure if they do it for all outside of OH. The cost of this kit is all over also https://www.boatandrvaccessories.co...lon-water-heater-door-conversion-kit-34-white
You get an oversized door to mimic the original Atwood and two side filler plates. They sell a standard smaller door for new camper installs.
I cut down a 2 x 4 to fit equally on both sides to create the correct opening and screwed them in place flush with the outside wood framing. Note: You must include the thickness of the retrofit side plates when cutting the boards to close in the opening.
The side panel filler plates. NOTE: The picture below shows four screws in these panels. I created lineup holes to ensure these plates return the same way once all the butyl tape etc., is in place. If these plates shift position up or down in relation to each other, the heater will not fit in the hole correctly. The door hinge holes must align with the side plates and the heater flange.
NOTE 2: Due to the mounting location of the T289SR, the top of the heater mounting flange runs into a high ridge bump in the siding. This large bump does not let the heater set flush to the frame wood. I used a large C clamp and 2 x 4 to flatten the large siding bumps flat. Then the heater will be set flush with the wood frame. The old Atwood did not matter as much, as there were no side filler plates. If your floor plan has the water heater pass through this large set of siding ribs, I suggest you flatten them.
Next was to deal with the water piping changes needed. Dometic flipped the inlet and discharge from being stacked to being side by side and from female thread sockets in the tank to male threads on a pipe that hangs out beyond the tank. On a new camper, this is not a problem; on a retrofit, it can create some piping opportunities to overcome. Each camper floor plan may have different issues to work through when dealing with the piping tie back into the existing camper piping. The newer Sunline campers often have a deeper cabinet where the water heater is so I could accommodate the added depth. However, tying into the existing hot and cold piping created a few revisions to get it correct.
Here is the first version. I thought this looked good outside the camper, and I'm using the two-valve heater bypass setup instead of the one 3-way valve and check valve of the older version.
While it looked nice and neat, the hookup inside the camper was not good; it would not work. Here is version 2; it did not work either… a bummer.
So here is the "third" version that did work. Yeh! This piping should be self-draining into the tank, not creating a natural water trap. The water needs to drain back into the heater, not stagnating when not used, the camper drained, and to help with winterization.
More in the next reply.
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, we are the self help group. 
