While I don't have this model, I assume the basic premise is the same on the 3570RS Bighorn. However, as far as I can tell, the Anderson valve did not have the vent hose attached and I've since had to replace that guy with the BrassCo one anyway. Therefore, I have no discernible vent available for me to manipulate as described in the previous entry. I am wanting to fill the 75 gallon tank with water from my cistern using a pump in between the two. The line is definitely getting pressurized and I've gone to the trouble to call back to Elkhart for support at which time I was advised to open the faucets, which I tried. What that demonstrated is that when I've got water going into the fill port the water comes out the faucets (should that be happening with the valve on "FILL"?). If I close the faucets, the line pressurizes. I have consulted the Water Systems Guide v1.2 and studied the diagram in there, but short of digging into the soft, black underbelly of this beast, I have no clue where to find the "Fresh Tank Vent" line. I am thinking this shouldn't be this difficult...
