My toilet will not flush unless I unscrew the studor vent, then you hear the air and feel it pulling in the air and the toilet flushes. We have replaced the studor vent twice and the same thing happens, when we screw the vent onto the pipe. If the vent is left off, all works. This has worked properly for two years when we installed it and now I am having problems with it. What can I do to fix this?
