I am having a problem when trying to change an existing York (4) wire manual themostat to a Honeywell (4) wire manual thermostat. The existing wires are RED,WHITE,YELLOW, and GREEN. This themostat works but temperature setting is not accurate and it is almost thirty years old. I am trying to replace with a New Honeywell manual with the same specs. Everything works but the oil burner. The fan on and the cooling works, but the heat does not come on. The R, W, Y ,G are the same as on the York. I reinstalled the old thermostatand back to normal. I know the Red (power) and Green(fan) are correct. Do I have to reverse or jump terminals to get this to work? Th installation guide says nothing about this and I am not about to just expeirment. Has antone run into simular problem?

NorthernHeat

White is the wire that turns on the furnace and Y is for the A/c. It should work. Does it work if you jumper R-W? If so you must have a bad stat.