I modified my plumbing for more reliable winter camping. I added shut-off valves to separate the hot and cold lines to the outdoor shower from the rest of the system and added a more convenient main shut-off valve. One of my major disappointments about my build was exactly this issue including putting the filler cap for fresh water on the rear of the drivers side. Not only is that the dirtiest place for it, but with essentially the EB50 interior why run it through unheated cabinets in the rear drivers side before turning inboard and connecting to the fresh water tank under the bench seat??? It could have just as easily be put directly in line with the fresh waster tank!!!
Before the mods it looked like this. On the left you see the drivers side rear wheel well. On the right you see the gray water tank behind the sink.
The line on the left goes to the filler cap. At the Tee the line turns to go to the fresh water tank and straight to the sink area. Note there is not enough room for a shut-off valve to the cold shower faucet. In the right photo note no attempts during the build to avoid low spots in the cold water line.
Below are the same locations after the mods.
The new main shut-off valve is just upstream from the Tee. I also made some mods not shown to ensure gravity can successfully drain the line between that valve and the filler cap when the drain stopcock is opened that is located under the van near the filler cap. Note some of my work was done using brass fittings and stainless steel clamp rings, similar to what SMB used except they use copper crimp rings. The crimping tool for the clamp rings is more compact, but in the end I would not do it that way again. Much of my clamp ring work was done on "sub-assemblies" that were then installed. You also see in both pictures Flair-it plastic fittings (e.g. the hot water line to the shower), and also clear PEX tubing purchased from Evergreen RV in Seattle. Those fittings solved the tool space problem! The clear tubing is "PEX a" whereas SMB uses less flexible "PEX 1a". These fittings are compatible with either type of tubing, but PEX a is less cross-linked and easier to work with. Being clear is great for checking whether the lines are clear of water too! I am pretty sure all three fitting types are approved by the Nation Plumbing Code, but you get on the web and see much discussion about which are better than others.
With these jobs done here is how it works. In the fall blow out all the water in the shower fixture, then isolate them from the rest of the system that you expect to keep above freezing. I use a "blow-out plug" that can be purchased at any RV store. It is an adapter with male hose thread on one end and a tire valve on the other. I attach a bicycle pump to it. I open the faucets on the shower after flipping the two valves on top of the water heater to bypass it and pump until only air come out of the shower head. Then the bicycle pump and blow-out plug is removed, and the new main shut-off valve closed, so the line between that valve and the fill cap remains clear of water. Then running the pump and opening the sink faucets refills all the lines you will use when camping. Lastly, the water heater bypass valves are opened again. I have a 110v electric water heater under the sink, and the photo below shows those bypass valves. You may have a different type of heater located in a different place.
With my Propex propane heater installed next to the fresh water tank under the bench seat on the drivers side, which is open to the area where the new main shut-off valve is, there should be enough warm air circulating around everywhere the filled plumbing system is. That is because the heater inlet is actually a vent right on the heater, i.e. no tubing is used to get return cabin air from some distant location.
Oh, one last thing. To fill the fresh water tank in the winter, the main shut-off valve is opened, the tank filled via the filler cap, the shut-off valve then closed, AND the drain stopcock under the van near the filler cap is opened to drain the line from there to the shut-off valve. Done!
2008 E-350 6.0L diesel:
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Cruiser II Top, 6'7" inside, full-time upper bed w/ kind'a EB50 layout, cozy 4-season rig
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