2 Thermostats on one furnace
I would like to add a downstairs thermostat on my furnace. Will it hurt my electronic/programmable thermostat upstairs to simply wire another thermostat to the furnace? I understand the voltage would be sent back to it but it wouldn't go anywhere that it doesn't already when the upstairs thermostat kicks on. I was told it for sure wouldn't hurt the old dial thermostats but want to check and see if I am going to kill my programmable one. Any info on this would be appreciated.