Issues installing Honeywell TH8320WH thermostat

Hello all,

I had the Honeywell TH8320WH thermostat installed at my old house using 5 wires. See picture #4. I moved into a new house that had old Honeywell lever thermostats with the blobs of mercury in them. My new house has 7 wires coming out of the wall. Only 4 of the 7 were used for the old thermostat (Photo #1) Can anyone advise me how to hookup my thermostat. Photo #2 shows all the wires coming out of the wall. Photo 3 shows the terminals for the TH8320WH. The thermostat doesn't even power on let alone control the a/c and heat. I would greatly appreciate any help. Thanks.

 

if blue wire was not used before, most likely it's not connected to the common inside the furnace. new thermostat does not have batteries and gets its power from your furnace.

Kill the power to your furnace and open the access panel on your furnace. Post a picture of the terminals inside the furnace.