Unknown water line valve- 2005 Classic

[Jammer]

My trailer has a third valve also. Like some others, it bypasses a check valve for the outside faucet.

While it strikes me as being a product of an overly clever engineering mind somewhere, I believe I understand its purpose.

When connected to city water, there is little reason to shut off the water to the outside water spigot, because freezing conditions and the possibility of vandalism or carelessness leading to an empty freshwater tank do not exist.

But when city water is not connected, it is possible to run in cold weather, and there does exist the concern that the contents of the freshwater tank may be lost due to mischief or foolishness. By leaving the valve closed, it is possible to have the outdoor spigot on when city water is connected, and off otherwise, which is a fairly convenient arrangement in most cases.

[Pahaska]

As previously posted, the valve isolates the outside faucet. When I winterize, I blow out the line to the outside faucet and then isolate it with the valve. Then, I open the faucet and leave it open until spring.

I use the outside faucet nearly every time I use the trailer. I have a very short hose that I attach from the outside faucet to the black tank flush sprayer. When I am getting ready to break camp, I first dump the black and then turn on the outside faucet and let the black tank flush while I am raising stabilizers and hooking up. By the time I am finished, the water from the black tank is coming out clear. Looking down the toilet, my empty black tank is always nice and clean.