I am having issues with my MD-8 dryer. It will run fine for a month to three months. Then it will go through a spell where I have to clean the fire rods every other day. I will do this for about a month. We do vacuum it every week. Clean the lint trays, vacuum inside and out of the dryer. I had a service tech tell me it was bad propane. I have had the propane delivery man tell me there is no such thing as dirty propane. Has anyone else had this problem?