Originally Posted by Bex
Now just one last item I think, then I can re-build my plumbing.
Why (in the diagram) is there a line joining the tank to the city/main line?
In our trailer ('66 Safari) the "bypass" around the pump allows the tank to be filled from city water, not drained. In your diagram, there's a separate drain for the water tank itself. There should be other drains for the rest of the system.
If the pump were turned on while city water was connected to the trailer, it would turn itself off. There is a pressure switch in the pump that tells it to run only when the pressure in the system drops below a certain level, which should be well below the pressure supplied by city water.
We used color coded 1/2" PEX with crimped fittings to replace the copper water lines in our trailer. Only problem is finding space to operate the crimp tool. In essence, we built each section as much as possible outside the trailer, then laid the assembly in place and connected it at a location where there was room for the tool to operate.
Be sure to draw a diagram (rough sketch OK) of the system you have before you tear anything out. There will be a little re-design necessary, because copper fittings will turn tighter corners than PEX fittings will. Just use the space you have and make something up that does the same job. This was especially true in the area near our water pump.