As the system heats up, you will need to bleed the air-bleed valves – a task which may need to be repeated several times over the following days in order to ensure all the air is removed from the system. Mix 1/2 cup table salt and 1/2 cup baking soda together, and pour down drain let sit for about 30 minutes (or overnight if it’s a tough clog), and follow with a pot of boiling water. Ken is the.