The Hyprotherm, L Series, Front Loading, Residential, Hydronic series is a front loading furnace with a round firebox based on the old style hydronic furnace. These coal only furnaces feature fireboxes that are 3/8” thick with ¼” end caps. The water jacket is 3/16” thick on the bottom and the sides and top are one piece of machine formed 1/8” steel with no welded seams. All Furnaces come with seamless water-jacket, new door latch with lockdown vault assembly. Cast iron coal grates. A 6” x 14” door provides access to the ash compartment below the fuel door. Two 1” supply nipples and two 1” return nipples standard. Includes a water level sight gauge and surface mount thermostat.