I was doing my preseason check on my stove and noted that in test mode that the feeder motor, blower motor, and combustion motor all started and ran for 2 min. then feeder turned off and both blowers went to low. The blower motor would switch from high to low every min. but the combustion motor just stayed on low I thought that should switch from high to low as well. I confimed this with a draft gage in the test hole. I was having problems at the end of last year with the stove lighting and not burning good and thought this could be the problem.