How do you open a clogged plumbing air vent to a kitchen sink?
He has also been up on the roof checking to see if there was a bird nest or something blocking the vent. He didn't find any obstruction. He used a plumbers snake and he could put it down through the vent until it reached water. However , the plumbers snake did come loose from the handle, and now it is in the vent. We don't know how to get it out, or if it will be a problem in the vent.
....and he did not take a hose up to the roof and run water into the vent. That is the only thing I see that we have not done yet. He has taken all the pipes apart under the sink and run the snake under there as far as he can, there is no clog under the sink that we can find. Those drain pipes are all put back together. The plumbing in the rest of the home all works properly.