Originally Posted by 360true
Cornelius... great ideas. Can you post pix of your valve? Didn't you have to drill the tank? Would the hole in the overflow alone do the trick? Thanks.
The valve I used came from Lowe's, along with the threaded to hose barb fittings and hose clamps. The overflow tube was cut a couple inches after the fitting where it comes out of the tank and the valve was installed into the tube.
To the left of the valve is the small hole drilled in the top of the overflow tube to act as a vacuum breaker for times when the valve is not being used. There were no modifications made to the tank itself, only the overflow tube. Just drilling the hole to create a vacuum breaker may be sufficient. If you decide to try just that, please let us know the results.
If you install a valve, be sure to ALWAYS have it open when the tank is being filled or water is being used in the RV. I only close the valve if I know I will be driving in a hilly area.