I put 2 Freedom 80 furnaces in my house in 2000. one is a 3 port, one is a four port. about 3 years ago, the electronic ignitors starting going out. i checked the ground, the propane pressure, cleaned the burners, and had voltage checked. I go through about 2/year/furnace. i can hear it fire off to the top port. sometimes it doesn't fire off the ports below and it cuts off and recycles. even if it uses the ignitor a lot in a winter season, shouldn't it last at least a season or two? i have found that if it only fires the top port, i can put my finger slightly in front of the gas orphice jet and it will fire the rest of the cylinders. Can you help with this?
remove burners and clean the crossovers. Propane is very corrosive to burners and flame sensors. it would be a good idea to order stainless steel burners if your furnaces does not already have them. While you are in there clean the flame sensor as well.