rgatijnet1 wrote:
dougrainer wrote:
rgatijnet1 wrote:
Not too unusual for the overflow to siphon out water from the tank. The tank on my Monaco did it so often that I finally just plugged up the overflow hose completely. That was six years ago and never had a problem. I have a vent right by the manual fill port so I saw no need to have an overflow hose that constantly siphoned off water from my tank.
Are you POSITIVE that the Vent next to your manual fill port is even connected to the Tank? Usually, when the OEM's connect a overflow that runs out the bottom, they do NOT run a 2nd overflow to the Fill port connection. Doug
When I fill my tank using the shore water and fill valve in the wet compartment I watch the manual fill port, located behind a door about midway up the body panel. Once the water starts to come out of the manual fill port, I stop filling the tank. The manual fill port has a vent located as part of the fill port. I did not say that the manual fill port was an overflow, I said it was a vent. If I do over fill the tank, excess water comes out of the manual fill port so to me it acts like a "full tank warning" and I shut off the hose filling my tank. Since it says that it is to manually fill my freshwater tank, and since water comes out of it when I am filling my fresh water tank with the shore water hose, I have to assume that the pipe is connected to the fresh water tank.
Here is a picture that shows the vent to the right of the gravity fill valve. I have to assume that it is a vent to the water tank. In six years with this coach I have never had a problem with the tank failing to pump water because of a vacuum condition.

I understand what you stated. MY point was, That vent next to the fill hose, is usually not connected, IF there is a vent line from the top of the fresh tank that is coming out the bottom of the RV. The pic shows the Vent, but as I stated, it is probably NOT connected. The REASON most RV makers vent the tank direct thru the floor to the outside is to prevent blowing up or bulging the Fresh Tank if the RV has City Water Tank filling option. IF the tank is not vented all the time, then you can either crack the tank or bulge it enough to destroy and bend frame supports around the tank. With your Pic of the standard Gravity Water Fill, they all come with the small vent connection. Some RV makers do run the vent hose up to that Gravity Water fill, and when of City Water Fresh tank fill, if you are not monitoring it, with the door CLOSED AND the 1.5 inch cap installed, the water pressure will build up and either pop the 1/2 inch line off the back side of the door and that water will flood your RV. Doug