I am unable to find my furnace's heat sensor. I need to clean it.It's a 1986 7900 Coleman series. Anybody know if this has a heat sensor and where it might be located?
it will be on the out side of the heat chamber, if it has one look at the wiring diagram on the furnace, usually its just the fan limit switch and the thermocouple, the fan limit switch acts as a high limit, switch
By Heat Sensor I expect you mean high-limit sensor. This will likely be a thermal fuse, about the size of a gumball, looking something like the link below. Most are self-resetting and are tied into the gas-valve to cycle it when the heat-exchanger reaches that limit. It will be accessible, but not necessarily obvious. So, follow the wiring to find it.
