[jcurtis934]

My furnace started to operate very similar. It would sometimes not work unless both propane tanks were turned on. I pulled out the propane valve/ignitor assembly in the furnace and found some stick bugs in the ignitor assy, but did not fix the issue. My issue was the propane valve in the furnace not being able to supply full fuel demand. I could adjust it to get it to work or adjust the main changeover regulator to get things working...but knew that it was time to replace the valve in the furnace. All is right with the furnace now. Point to be made here is that several things can cause fuel flow issues that can result in this behaviour of the furnace. Unless you know that the work was done with the right tools to diagnose and measure propane pressures, it's hard to know the issue was really found.