We would like to replace an old honeywell 5 wire thermostatModel 890121. But can't find one. We don't know what to get. Halp

SOURCE: replacing thermostat for central heat and air/ not humidifier

rh and rc should have a jumper between them.connect red to either.y=yellow g=green w=white and do not use the blue.your new stat will run on batteries.

SOURCE: got a honeywell t8400c thermostat

R--- rc or rh y--yellow g---green w--white red is power yellow is cool g--fan white is heat

SOURCE: rewire an old 2 wire thermostat to a honeywell 5-1-1 programmable

I connected the blue wire to the R and the white wire to the W on the old thermostat and shoved the new Honeywell 5-1-1 Day programmable thermostat up the first guys *** that i ran into at Canadian Tire

Thanks for your help

SOURCE: Help! replacing WeatherKing thermostat with Honeywell RTH230B

RC AND RH CONNECT BOTH WITH RED
Y TO THE YELLOW
G TO THE GREEN
W TO THE WHITE

SOURCE: I just bought a Honeywell

I just installed a Honeywell 5.2 Day RTH2310B Programmable thermostat and I had to deal with the same situation: 2 wires, one white one black. After reading the edvice in one of the blog, the solution that worked for me was: BLACK ON Rc terminal and WHITE on W terminal. My furnace is running fine now. Hope it helps.