HOT WATER CIRCULATING DEVICE
For those of us that enjoy dry camping, I am writing a description of a system that will circulate water from the hot water heater, back to the storage tank. If you think about this, in order to have hot water at your shower, you must sometimes run almost a gallon of water down the drain before the hot flows. This not only depletes your potable water supply, but also loads the gray water holding system. This system will eliminate that situation. It is very inexpensive, and not a difficult project.
Material and observation:
Approx 25 feet of ½ inch PEX tubing(varies coach model)
In my coach, a 2000 37 V, the shower is the furthest from the water heater. I chose to tap into the hot water supply with a ½ inch PEX Tee or you can use the shark fittings. Measure the distance by routing method from this location to the water hold tank which in my case is the front passenger side compartment. There is an inspection door at the vicinity of the shower valve. Cut the hot water line, and insert a tee into that line. In my project, I install a second inspection opening directly below the shower valve access. I cut my hot water line at this location, installed the tee, and fed the ½ PEX tubing straight through to the water tank without the sharp bend necessary working on the rear of the shower wall using the existing inspection door. A luan panel or matching wood completes the inspection door project. Run a ½ inch PEX water line down the wall under the shower, through the bath cabinet, under the refrigerator, under the kitchen cabinets and into the bay containing the water tank. This tubing is available at Home Depot along with the fittings.
You need to cut the water line feeding the pump, and install a tee so the electrical valve can when opened return water to the tank. I would suggest as I did that when you install this system, you install a shut off in the line feeding the coach so that in the event of changing the water pump, it can be done so without emptying the water tank. I chose to mount a momentary push button switch on my bath lavatory cabinet. This switch will furnish 12vdc to operate the water valve. I wired it into the pump circuit so it is only used during dry camping, or when the pump is used to draw water from the storage tank. Note, the pump switch needs to be energized to have the circuit functional. After installation to test, simply hold the momentary push button in and count to 12 slowly. You will hear the water pump start, and circulate water through the hot water loop. It will flow back to the non pressurized water tank. You will have hot water at the shower, the bath sink, and the kitchen faucet instantly with no waste of water.
If you chose to wire from another 12vdc source be aware that you could add water to your storage tank if hooked to shore water, but that is really not an issue because the volume is usually about a gallon.