I have a mobile home with a central A/C unit and natural gas furnace. They are currently operated by (2) old honeywell, mercury type stats. Wanting to convert it to (1) lennox model 81M27 programmable signature stat. I am confused on the wires. As each has only 2 wires , do I connect the 2 for sys. Transformer together and the others to 1st stage heating and cooling , respectfully?