Hello,

I bought a Honeywell TH320U1008 thermostat to replace existing Lennox 51H4001 thermostat. The Lennox thermostat is a 2 heat, 1 cool unit. The current wire designation is RH = red wire, O = orange wire, W1 = white wire, Y1 = yellow wire, C = blue wire and G = green wire. My current heating unit is an electric heat pump. The terminal designations for the new Honeywell thermostat for heat pumps is Y2, L, E, AUX, S1 and S2 on the left side with RC, R, O/B, Y, G and C on the right side. Does anyone know the proper way to connect my new t-stat to the existing t-stat wiring? Thanks, Mark

Did install instructions come with the honeywell?//I would use the post on the right side,, red to-r,, orange to o, yellow to y, green to g, blue to c, with a jumper from rc to r

Be sure to turn off breaker to furnace before messing with any tstat wires
You will prob need to read instructions and program that you are using the o and not the b

Someone will be along in awhile and tell us if I`m wrong

Thanks wmproop, I have connected the wires as you have directed, but I still have one wire from the old thermostat, W1 = white wire that was in use. No W1 call out on the Honeywell thermostat.