Plumbing Schematic for 72 Overlander

[PizzaChop]

As the proud new owner of a 27' Overlander (1972 International model), I am a bit confused regarding the overall flow of water in my unit. I have the rear bath model with 2 drain valves in the rear and 3 drain valves under the kitchen sink, next to the fresh water tank. I have finished re-plumbing most of it with copper (the previous owner had used braided plastic hose) so I have a decent idea of most of it. I'm just not sure how how the fresh water tank and shore inlet work together. Obviously there must be a check valve to prevent water from escaping through the shore inlet when using the fresh water tank.

Does anyone have a drawing or the patience to explain the flow of fresh water to me?

Also, my pressure regulator is not there. (Someone thoughtfully replaced it with some cpvc.) Would I do better to use one on the shore inlet or should I go back with the original? (It looks to be a bit tight in there.)

Thanks for all the great info on this forum!

[Inland RV Center, In]

Ron.

You can get a 73 service manual from Helen Davis at 937-4928885.

Thge plumbing section is the same as a 72.

Andy

[Chuck]

Sounds to me like you've already got it. yes, there is a check-valve that keeps pump-water from escaping out the city inlet. On my unit, the check-valve/pressure regulator is one unit. Who knows what's been done to yours, though, right? Well, I can't help you with the exact locations of things, because my trailer is different, but on mine, the regulator is also very hard to reach. and the check valve leaks a little. Cheap solution to both problems: an external pressure regulator, available at Wally-World, and a threaded cap that fits into the city water inlet, which allows the water pump to pressurize the system without water leaking out the city inlet. cost me 2 bucks from the local RV supply store. (also keeps critters out of the supply line).

Oh, and I believe there is also a check valve built into the water pump, which keeps the city water from filling up and overflowing your fresh water tank.

[PizzaChop]

Gentlemen,
Thank you for your kind input. However, had I waited two days, I wouldn't have needed to ask the question now that the entire plumbing behind the toilet is EXPOSED! (Yes, I thought that I should investigate a soft spot I noticed while removing closets to make way for bunks and before I knew it, I had had everything out on the left rear of the trailer and my worst fear was confirmed.)
I guess my next question (and I haven't checked previous threads yet) is what is the most efficient way to drain and remove the water heater so that I can replace the flooring beneath the toilet and water heater.
Also, is it okay to replace only half of the bathroom floor, assuming the other half under the tub is okay?
Thanks for all the help!