I have a witfield advantage 1988 yr. It run 30 min. And shut down. I found low temp switch was problem, I bypass with jumper. And stove works but it will run alk day if you let it run were it starts at ( medium ) just fine but if I try to adjust fan speed or temp the stove shut's off and then about 5 or six try's and it will stay running if you let it run were it wants ( medium ) runs for hours but don't try to adjust it. Can anyone help me with this problem please.