I have a 2206 towlite
Like many of you I have the 6 gallon water from Atwood with a rectangular door
They no longer produce this water heater when I had the tank go bad and was looking for a replacement
I installed a suburban brand gas / electric one which was square in shape and the tank faced the other direction
By redoing all the plumbing including modifying the fresh water pickup tube to the water pump and relocating the water pump, it fit!!!
I counterflashed the hole of the original water heater to the new water heater with 24 gauge sheet metal for waterproofing behind the water heater door
I wanted to use the original door and frame so I modified it by cutting a new flue exhaust hole and covering it in stainless steel screen
The water heater and water pump area are now covered in sound proofing foam and plywood for noise and access doors for servicing

In the design phase of a hybrid hot water heater system
I’m going to add a tankless water heater made by surburban to my tank water heater which is also by surburban that I just replaced

The reason
Best of both worlds , limited water during boondocking and unlimited hot water for showers
Want the tank water heater for short burst of hot water for dishes
Want the tankless water heater for more hotwater than the 6 gallon can supply for a longer shower
I will be plumbing them in series (cold water into tankless w/h then into tank w/h) using the tankless water heater as a booster for the tank water heater

That's an interesting concept, camp. I hope you will post pictures that show your installation, maybe some during progress too!

Is the tankless heater powered by propane too?

- Jack

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Hi-Lo 1707T - Tire Minder TPMS on Tow Vehicle and Trailer, 300W Solar Battery Charger, Equal-i-zer WDH, Progressive Dynamics Converter, Fan-Tastic Fan, LiFePO4 battery 12V DC Electrical System, SoftStartRV mounted on A/C
2024 F150 Platinum FX4 3.5L PowerBoost SCrew

Tankless water is propane and 12volt ( 12volt is for control board)
I happen to have room to install both types of water heaters in my 2206 under the couch/bed

The problem with tankless w/h is you have to have water on for 10 seconds at 1 gpm for them to work
And at a set temperature can’t add any cold at fauset to adjust temperature also if you turn off shower between soaping up and rinsing off you get cold water for 10 sec ( important if your boondocking)

__________________
Les & Patricia
2006 22ft towlite (replaces 97 21TL)
2006 Toyota tacoma pre-runner 4.0 L V-6 quad cab
w/ 98 chevy Powervision towing mirrors
2017 Chevy Silverado 1500 5.3 v8 (replaces Toyota)
2 Hobie mirage pedal drive kayaks

Only Truma tankless water heater fixes this problem by using a pre heated tank in there tankless w/h which dealer install only and $2000
But I found a solution stay tuned ��

__________________
Les & Patricia
2006 22ft towlite (replaces 97 21TL)
2006 Toyota tacoma pre-runner 4.0 L V-6 quad cab
w/ 98 chevy Powervision towing mirrors
2017 Chevy Silverado 1500 5.3 v8 (replaces Toyota)
2 Hobie mirage pedal drive kayaks

The surburban tankless water is the make that will work
Operates with 1/2 gpm set at 130 degrees which means you can add cold water at fauset

__________________
Les & Patricia
2006 22ft towlite (replaces 97 21TL)
2006 Toyota tacoma pre-runner 4.0 L V-6 quad cab
w/ 98 chevy Powervision towing mirrors
2017 Chevy Silverado 1500 5.3 v8 (replaces Toyota)
2 Hobie mirage pedal drive kayaks

Plus if you put it in series with a tank water heater you won’t have a shot of cold water when you turn on and off the shower while boon docking

__________________
Les & Patricia
2006 22ft towlite (replaces 97 21TL)
2006 Toyota tacoma pre-runner 4.0 L V-6 quad cab
w/ 98 chevy Powervision towing mirrors
2017 Chevy Silverado 1500 5.3 v8 (replaces Toyota)
2 Hobie mirage pedal drive kayaks

Difficulty of install between 1 and 10 it’s going to be a 10

__________________
Les & Patricia
2006 22ft towlite (replaces 97 21TL)
2006 Toyota tacoma pre-runner 4.0 L V-6 quad cab
w/ 98 chevy Powervision towing mirrors
2017 Chevy Silverado 1500 5.3 v8 (replaces Toyota)
2 Hobie mirage pedal drive kayaks

Sounds a hell of a project, Les! I didn't know about the 10 second delay time in these heaters. Way back, when I was in high school (the 50s), my Father (US Army) was stationed in France.and we lived in a home that had a tankless heater in the kitchen. It was above the sink and would light up almost immediately when hot water was turned on. Since it was visible, you could see the burner. Kind of spectacular as I recall.

- Jack

Also I have to say I’m a little OCD about the water systems on rv s
I was never happy with pressure changes as the water pump starts and stops so I installed a rubber bladder pressure tank( 1 gallon in size) that is pre charged with air at 27 psi ( they use these on wells)
Which keeps a even water pressure while using my fresh water pump on my trailer
Next I did not like I the hot water temperature veries when you start pulling water out of the small 6 gallon water heater and your incoming water in colder than normal so I installed an automatic adjustable thermostatic mixing valve on outlet of the rv tank water heater ( they use these on boiler systems) to keep the temperature at a set point also great so if the temperature went to high in the water heater it would never burn you

I wonder if a 10-gallon water heater would fit. I've never actually seen one.

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My Great Wife Joyce
2018 Jayco Jay Flight 21QB
Formerly owned 1705T and 2310H
2012 F150 4X4 SuperCrew EcoBoost w/Leer Cap
Reese WD Strait-Line Hitch
Amateur Radio K3EXU