I have an old house with old thermostat and no info on either. Wife bought a Honeywell 24V replacement. She wired it turned it on the the wall got hot and smelled funny...she turned the main off rewired old stat and symptoms disappeared. The problem with the new stat is there is a RC/RH jumper cable and a Y cable premanufactured. We have no Heat pump. Took the red jumper off put our red wire on the RC. Still wall got warm but not as hot. The yellow premanufactured wire says its removeable but it won't come off so I added out Yellow wire to the existing one. Besides that everything is wired well but we can't figure out why its obviously getting too hot. Any thoughts??? Wrong stat? Our old stat says 30V MAX so the 24 should be ok. Right? The directions for the White rogers stat are awful and the phone # to call for service (on the box) is out of service. I'm not liking this at all.
P.S. This is the wife writing you. My husband is working on another project.