One of the wires is off my thermostat - white rodgers type 1F80-361, consequently my heater is off. I would like the wiring diagram for this model so that I can place on the correct post.

What color wires are at the stat and what terminals are on the stat?

White wire at the W post, a red and black wire are at the RH post, and a red jumper wire that is on at the RC post, but what post should the other end of the jumper wire be connected to?

Emidio

I don't understand why 2 wires are on RH. With nothing connected to RC other than one end of a jumper, & the other end disconnected, I could understand hot having cooling. But I have no idea as to why you don't have heat.

Was this stat working OK and then just stopped or was it off the wall for painting or some other reason. You may have to look in the furnace and locate the terminal board to see where the wires are connected at that end. It would be normal to see a jumper between RH and RC.