There are two appliances that you want venting into one chimney liner. You have a furnace and a hot water heater and want to install a stainless steel chimney liner. How do you connect them both to the single chimney liner?
Most water heaters have 3″ stove pipe, some have 4″. Most furnaces have stove pipe that is any where in between 5″and 8″. You can purchase at a local plumbing store a stove pipe “Tee” or “Y”. This is the easiest possible way to connect both appliances into one chimney liner.
Once the snout of the chimney liner comes out of the chimney horizontally through the thimble, you can use one of the following to attach your two appliances together, whether it be a water heater and furnace to the same chimney liner or something else.