I have an old Honeywell thermostat (rotary type). There are two wires, what seems to be green and maybe offwhite/yellow. They're coming off a late 1940s gas furnace with fan blower. I wired the yellow and green wires to the yellow and green terminals and the furnace and fan came on and never shut off. I had to disassemble the unit to shut it off.

Is there another wiring possibility? I programmed the unit before I stuck it on the mounted base, could that have done anything?

This is my Mom's home in north Jersey, so there's no AC.

Thanks for any help!

Use W and RH for the terminals. It does not make a difference which wire goes where since there are only 2 wires.

See wiring 2.3 first picture right side

http://customer.honeywell.com/techlit/pdf/69-0000s/69-2060EFS.pdf