Batbc Report post Posted March 18, 2012 I have a 2006 Fleetwood Pace Arrow with an Atwood furnace model 8531-IV. Until today it worked fine. Now it ignites but quits after a few seconds and cycles through 3 times. I notice then a red flashing LED on the motherboard after the cycle with 3 flashes then a pause before 3 more. The manual says the code indicates "ignition lockout fault". What can I do? Share this post Link to post Share on other sites
dickandlois Report post Posted March 18, 2012 Batbc, You mention that it has worked fine until today. Has the furnace been off for a length of time before today? Share this post Link to post Share on other sites
ronliz Report post Posted March 19, 2012 The problem is usually the Computer chip board is not working and has to be replaced. These boards are notorious for going out. Share this post Link to post Share on other sites
campcop Report post Posted March 28, 2012 Check the ignitor also, the air gap might be too large or the porcelain on the ignitor/thermister might be cracked... Share this post Link to post Share on other sites
cobrafang61 Report post Posted June 16, 2012 Gas furnaces use a flame rectification pilot proving system, the spark is AC initially, however as it passes through the flame, its rectified to a DC signal, via Flame rectification. A flame isn't a great conductor, but it allows millivolts/milliamps(not much, easily disrupted) of a DC signal to be sensed by a sensing rod, and /or ground via the pilots assembly etc. There will be a ground, or sense terminal on the ignition module or board. The signal in DC returning on ground/sense is what proves a flame exists ,or the pilot and is safe to then transition to full burners-- this is a good thing, especially with propane. There are centrifugal pressure or a sail switch that proves the induced draft motors running and says go to spark, but not always. Sometimes the pilot drops from the pressure, centrifugal or sail switch not proving a induced draft exists, especially if its a pressure switch. The orifices where the tube attaches on the induced draft blower assembly, carbons up and requires a tiny drill bit to ream out the tough carbon plug/deposit, sometimes they are partially blocked causing a wavering and on/off as your as well. It can be several things without seeing it, impossible to tell definitively, but these are where to look and how. Share this post Link to post Share on other sites
