The early oven concepts included a coiled-resistance wire heating system. One major problem: the tightly wound spirals of heat-concentrated wire kept failing. Compounding this reliability issue was the fact that the wire coil acted like a spring. When the element broke, it would touch an electrically conductive component within the oven. Not only would the heater short out, but the reliability failure became a hazard to the oven’s operator.

The first order of business at Thermal Circuits was to do a root cause analysis as to why the reliability problem. Thermal Circuits determined the open-wire element was running in excess of its thermal limitation. To rectify the situation, an etched-foil-element was designed. The same energy (watts) of the wire element was spread over the flat-foil conductor’s larger surface area. By not confining the wattage to tightly spiraled coils, the new etched-foil-element heating system runs cooler and lasts longer, still with the same power.