I have a Trane unit and the ignitor does not produce a flame. The unit's blower runs and keeps the house at 62 degrees, 29 degrees outside. I have had this same problem once before and I was told that all that was needed was to clean some part in the furnace. Do not remember what that part was. I changed out the filter just to make sure that the filter was not the problem, with no luck. Any help would be appreciated.