Tankless Water Heater Install
I have finally finished the replacement of our leaking Atwood water heater with a tankless propane heater. A tankless heater is not for everyone, but for anyone interested, it is not a terribly difficult task.
I started by removing the old heater. The main difficulty with adding a tankless heater is that they are several inches narrower and shorter than the old heater. I had a friend make a mounting frame that fit the new heater and weld it in place. I then made a new base for the heater out of plywood; it is rated to be installed on a combustible surface. Notice in the picture that I moved the new base up so that the extra space is at the bottom. I did this so the exhaust of the new heater would line up with the existing opening in the outer bay door.
The new heater is one I got from Amazon--not a name brand. While I would prefer a name brand unit, I got this for almost nothing to test, and so far have been happy with it (have used it since early last May). It has a wired remote control panel that can be mounted inside the coach, but so far I have just left that in the bay. I attached the heater to the existing frame (top and left) and the new frame (bottom and right) with self drilling screws and a layer of butyl sealant tape between the heater and the frame. I had to re-bend the propane line to make it line up with the connector on the back of the heater, but I did not have to cut the line. I did have to alter the plumbing slightly, and the only electrical connection is 12v, connected to the existing wires. The old 120v line I capped off and terminated in a surface mount box on the side of the compartment. We used the heater as it is shown in the fourth photo, with the openings on the side of and below the heater, from May until this month. During that time, I left the old rectangular opening in the bay door as it had been, allowing the heater to draw air from around the edges of the opening that also served as the exhaust opening. This worked, but I never intended to leave it that way as the heater should have a dedicated opening to draw fresh air from the outside. I also do not believe it should be allowed to draw from inside the compartment.
This month I finally got around to finishing the project. I added a round, louvered vent I got from Amazon in the outer bay door. I used a 4" hole saw to make the opening and added the vent with 3M Marine Adhesive 4000 to seal it and three screws to hold it in place. I then added thin steel plates to close up the openings below and to the right of the heater, keeping it from drawing from inside the compartment. A attached those with butyl seal underneath, self drilling screws, and 3M 4000 to seal the cracks. Unfortunately, I only had 3M 4000 in white, which looks a little funky both inside and on the outside of the door. I also sealed around the rectangular opening using some self adhesive foam sealant that I had on hand. It isn't pretty, but it doesn't show unless the bay door is open. I also hope to find something better at some point.
Overall, this wasn't the easiest but was far from the hardest project I have done on the coach. We mainly use the heater for showers and for washing dishes. The lag time to get hot water isn't bad, but it takes some getting used to. It is great when we we have full hookups, since we have unlimited hot water, but it probably wastes a little more water because of the cold bump every time it comes on, so it is not quite as good as the old heater for boon docking. It also costs more to use because we always run on propane, even when we have electrical hookup. On the other hand the propane usage is minimal. I am not sure if I would have tried it if I had to pay full price for the heater, since I could get a tank type propane/electric for close to the same price, but I don't regret changing to tankless.
Topic: Tankless Water Heater Install