scope:

Description of Driving Event:

During the cerachrome insulation baking process of three injector/chamber assemblies, severe oxidation of the assemblies was observed. The required baking temperature, per MTS 1324, is 600 deg F for 48 hours. It was discovered that the oven had failed, allowing the temperature to reach an estimated 1400 deg F. A proposed design change will reduce the possibility of this happening again. The modification incorporates a direct 440 VAC cut-off initiated by series redundant overtemperature shutoff circuits, as well as, a series redundant shutoff of the temperature control.