Troubleshooting Guide For Gas Forced Draft Furnaces With Integrated Fan Controls This guide has comprehensive step by step instructions that walks you through each sequence of a furnaces operation Each step explains what to test and possible failures This guide is meant to help technicians trouble shoot the cause of gas fired foced draft furnace failure This trouble shooting guide is for most problems with a very basic draft induced furnace with an integrated fan and ignition control board Some furnaces have variable speed fans variable speed inducers multiple pressure switches and a multiple stage or modulating gas valve Some trouble shooting may vary for these furnaces This troubleshooting guide does not diagnose modulating components Guide is made of thick cardboard stock with metal corner rivets and measures 85 inches tall by 6 inches wide