fresh water tank overflow syphoning tank dry
Let me start by stating that my overflow in a tube sticking out the bottom of the underbelly of the trailer. I have always just filled my tank untill water starts to flow out of the tube. It would alw...
Forum Discussion
DutchmenSport wrote:
Normally, isn't the overflow pipe also the vent pipe? If you close off the vent pipe with a valve, wouldn't that cause a vacuum in the tank and then nothing would pump out with the on-board pump.
Most tanks have a drain valve and an over-flow/vent. The end of the over-flow/vent is usually placed higher than the top of the tank, and installed in such a way that the direction is always upward, never down. Down could cause a vacuum in the tank.
Even if your tank is siphoning, there has to be a secondary opening somewhere to prevent the tank from vacuuming up, unless when you disconnect the water hose and the air is coming from there. Now, if you fill is gravity fill, then it does have the secondary opening to allow siphoning to occur.
So, I guess what I'm asking, are you sure that tube UNDER the trailer is not the drain valve and the vent is somewhere else? I've never heard of having the vent tube 'below' the object it's venting, only above it.
What he said.
