Recently bought a house. It has forced hot air and I want to replace my old honeywell stat with a new honeywell stat. the wire has four colors red,black,yellow and green. I've never seen anything like this before. Usually the wire has 3 or 5. so I thought it was going to work, but the stat has only 3 connections. Well I wired it anyway. Now the heat doesn't shut off until I shut the switch for the emergency shut off. The heat just runs and runs. :confused: