The bottom burner on this oven does not work. The range and the broiler work fine. When you select bake, the element glows orange but the gas never comes on. If you tap on the gas control valve, it will come on, but will go off in 36 seconds and is very repeatable. I checked the orifice and it is fine, I also replaced the control valve (WB19K36) and the symptoms remain the same. It appears that the temp control and brain are working properly as if I heat up the oven with the broiler, then switch to bake, the oven will show that it is preheated to the correct temperature. It seems as if I have two bad valves, but I tend to think that is not logical. I have checked all connections and they are solid. What do I test from here?