I have a lopi Yankee in my cellar. After an hour the fault light comes on and the # 2 green light flashes.I found a trouble shoot doc on line and it says it is the 120 degree snap disk above the exhaust blower or,the draft flow switch. I have replaced both but the problem still exists. Happens again in about 1-1/2 hours. I am at a loss,anybody have any ideas.