[alfabits]

H Gorgon. Actually the vents are open fine. I had the tank out again yesterday to fix a small leak coming from the vent tube where it comes out of the tank. I had to re-solder around the tube. I checked all the openings with air and filled the tank with water to remove all fumes before soldering. I don't understand how the vent works. It doesnt vent to the outside. It appears to only acts as a loop within the system. If you don't vent to the outside and you remove fluid (volume) then you will create a vacuum.

George