I am working on a Meiko B190P-n conveyer dish machine. It has a wash tank and an auxillary tank. Neither tank comes up to temperature. I verified the gauges. All of the elements are free of calcium and drawing the correct amperage. I checked the exhaust system to see that it wasn't pulling to much air. The water in the tanks is not diluted by too much make up water. The incoming water is 135 degrees. The water in both tanks comes up to 155 degrees. I need at least 165 degrees. The question I have is will a heating element loose it's ability to heat after a few years?