The Hyprotherm, Top Loading, Residential, Hydronic (coal only) series is a new concept based on our Chest Loading series. All of these top loading furnaces come with easy opening, gas spring assisted fuel doors. They have 3/8” thick fireboxes which set vertically inside the water jacket. This allows for the Top Loading fuel door and an economical complete burning fire. The water jacket bottoms are 3/8” steel just like the fire box, and the sides and top of the water jacket are 3/16”. They have cast iron shaker grates and are designed to burn coal only. They have removable ash pans to make ash removal simple. Each furnace is pre wired with only one connection to a power supply necessary, making them basically plug and play simple. Each comes with; lock down vault assembly door latch, two 1” supply and two 1” return nipples. Also includes a water level sight gauge and a digital thermostat to control the combustion blower.