I have a Lopi Freedom, the air control lever down the bottom of the stove is kind of hard to move in and out. Is this normal? I have to give it a good yank, or a good push depending on which way it's going. My fiance wanted a lesson on how to work the stove so she can run it when I'm not around, so I had her move the control and she had trouble moving the lever, she's not weak and could do it, but had trouble at first. I always shrugged it off as that's how it's suppose to be, but maybe it's not? Can it be taken apart and lubed with something?