Mystery "port" in Fresh Water Tank gushing water.

[Otis Mac]

This is my first time actually reaching out for help on any forum. However, I have appreciated many posts in the past and I'm hoping someone will be able to enlighten me. I'm looking forward to being part of the RV Forum community.
I bought a 2013 Winnebago Vista 35F about two years ago, having traded up from a camper trailer. Due to Covid, we barely used it at all in 2020 and used it for a month in one location in 2019. It's time to get out there.
Upon filling my FW tank (through gravity feed) to sanitize it, the overflow tube began to spew as expected. I pulled the hose out and went on with the task at hand. I soon realized that water was no longer coming out of the overflow but was gushing out of another 'port' of some sort. This mystery 'port' did not have a valve or stopper. It is roughly a half inch in diameter and unthreaded. I was completely unaware of it until now. Can anyone tell me what the mystery port is for? Is it supposed to have a valve or some kind of cap? Or not? Presently I am unable to fill the FW tank and I'm desperate to find a solution so we can roll out on schedule two days from now (Mothers Day). I appreciate your time and experience. Thank you, Otis Mac.

 

[thelazyl]

Our motorhome has a tank water drain plus 2 "low point" drains for cold and hot water - could it be one of those that's open? Our low point drains are in the wet bay.

 

[SpencerPJ]

A picture would be priceless. Try to snap and upload

 

[Isaac-1]

Sounds like a low point drain for winterizing, some (generally the ones from the better manufacturers) have cut off valves, other more economic models may only have threaded caps that screw on.

 

[John From Detroit]

1'2 inch is generally the water heater drain. but .... it could be something else.

My RV the tank had two outlets one was simply plugged. both were 1/2 inch

I put a valve and a suction line (Bad design of tank) in there so I could truly drain the tank.

 

[Gary RV_Wizard]

1/2" hoses with no valve at the end surely sounds like a low point drain. There are usually a pair, hot & cold, and exit under the RV. They often have valves somewhere above, perhaps somewhere near the "city water" use/fill valve. There is also a water drain valve for the fresh tank - that may be open. Last, I think you have an antifreeze siphon valve that can be used to suck antifreeze into the water lines from a jug of antifreeze. This can spew water if left open and the pump is not running. It is explained in the Plumbing - Winterizing section of your owner manual. It may have been left open if the coach was winterized before last winter.

Your Vista owner manual should show all these if you have them - see the Plumbing section. If you don't have that, get one at 2013 - Winnebago .

Please describe more where this mystery water hose is located, and maybe a photo of it and your water system controls in the "wet bay"

 

[X-Roughneck Strike 3]

Not sure but it sounds like it may be your fresh water dump valve. In my Winnebago Aspect There is a square 8 x8 " hole under my mattress foot to the dump valve handle.

If you are lucky enough to have the books the drain locations are all covered there.

Last resort Maybe you can online search as a Winnebago has lots of info on the web.

JD