Inside the combustion chamber of a Hotsy hot water pressure washer, and below the
heating coil, sits a thick layer of insulation, commonly called the Pancake Insulation. This bottom coil insulation protects the burner system components from possible damage caused by the high temperature flame within the burn chamber that is heating the high pressure water flowing through the heating coil. This pancake insulation should be replaced when replacing the heating coil, but can also be damaged by excessive unspent (or not burned) diesel fuel that has been sprayed into the burn chamber, but not ignited properly by the electronic igniter or transformer.
