Kurt at koegel plumbing is amazing!! should have called him sooner thank you!!! I'm going to try the baking soda + vinegar tonight, let's hope for a good volcanic unclogging :). There are various types of culvert, they can be stone, brick and pipe most of these can be surveyed if you are unsure please. Have you had any of the following problems with your boiler? Upgrading your insulation help keep the cold out. For all your heating and cooling needs, call or contact us today! Alex.