My furnace is a 1990 Payne 394Jaz060080. It has had a problem that comes and goes. It will sometimes not come on in the morning or if it has been off for a while. You have to turn it from heat to off then back to heat. Sometimes 2-3 times before it will come on. Once it is warm it cycles normally. It may not do it for weeks then do it 3 times in one day. It is so old it has no intricate lights to indicate a fault.