HELP. I purchased an ACE ATX1500 series digital thermostat to replace my Honeywell dial thermostat. Not sure now if it is compatable with my system. The instructions say, "It cannot be used with 120 volt heating systems. Designed for use with 24 volt and millivolt systems. Limited to a maximum of 1.0 amps." My furnace is a Lennox G12 series (5875D, 00636) and my air conditioner is a Lennox (model H583111OFFP). The instructions for this thermostat has 3 to 4 diagram options with jumper wires between some connections. Not sure what to do. Not comfortable with putting a "jumper" between connections in thermostat. I got a really good deal on this thermostat and I usually do most work myself. Any help or suggestions would be greatly appreciated. Please e-mail me = don't know if I will be able to check this message board again.