hi guy,s wonder if anyone can help, a diplomat dishwasher adp8312,customer say,s it takes about 4 hours to complete on checking it i found upper spray arm not circulating ,cleaned it no better, and also machine not heating, checked heater, its ok, checked thermostat( 4 point connection, with resettable button ) but it only reads closed circuit on 1, the other is open, even after a heat test, is the stat at fault