When I started up my Raypak PR267 low nox heater this week the heater was firing but cutting out frequently. I had this problem a couple of years ago and cleaned the pilot and rewired the frayed ground wire between the pilot and the valve. The unit has run well up to now. Today I proceeded to clean and refresh the ground connection since the green wire was cooked black. After reassembly, the unit would not even spark. The fault code FFL comes up and then nothing. I tried taking out the pilot and making sure the pilot was not blocked. I reseated all the wires on the gas valve to make sure they were making good contact but I stuck with the FFL fault upon reseting the power. Anybody have a guess what I did to cause the FFL error.