Hey everyone, I received my Brinsea Octagon 20 and I was pretty excited to set it up until I discovered that the vent is stuck. The adjuster should just slide left or right, but it won't budge at all. I can't even pry the vent itself open. I emailed Brinsea, but they aren't responding. Am I missing something here? This is how the vent should work: I'm open to ideas if someone knows how to fix it.