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View Full Version : Old stats wiring to new programmable unit


jaunio
Nov 24, 2009, 03:20 PM
I replaced my old lennox gas furnace with a new 95% efficient unit, electric pilot and with no a/c and wired the old lennox mercury thermostat using the two wires from the previous hookup. I have a new Hunter 44110 programmable thermostat with 5 connections, RH is 24 volts, RC is 24 volt cool, Y is the a/c compressor, W is heating and G is fan. Where do I connect the two leads from the furnace to the thermostat? The instructions state that the stat will work with 2,3,4, and 5 wires. Stat also has 2 aaa batteries for the readout? :confused:

mygirlsdad77
Nov 24, 2009, 03:51 PM
The red wire from furnace goes to rh on new stat(you can leave the jumper between rh and rc in or take it out,doesn't matter. The white wire from furnace goes to W on new stat. If the colors of wires from furnace are not red and white, just trace them out and see which is hooked to r and which is hooked to w on furnace, then hook up correspondingly to new stat. Good luck and let us know how things work out.