In search of help with hooking up a Nest Thermostat E. I have seen several threads seeking solutions for similar issues and have troubleshooted with their proposed solutions with no luck.
I am replacing an older model Honeywell Thermostat which was battery powered (Model: TH4110D1007) with a Nest Thermostat E. The Honeywell did not have a c-wire connected, and used a set of AA batteries for power. The Honeywell had only red, yellow, green, and white wires connected.
After pulling off the Honeywell thermostat I located an unused blue wire behind the wall plate which runs to my Rheem furnace (installed in 2006). I connected the previously unused blue wire to the C terminal at the furnace circuit board and at the thermostat, however it is not powering up the new or old thermostat (without batteries and with c-wire now connected).
I have attached photos of the thermostat hook-up and furnace circuit board. Again for clarification, the blue (c-wire) was previously unused, all I did was hook it up to the furnace and thermostat c terminals. Additionally, the extra red and white wires at the furnace run to my A/C unit.
Seeking any possible solutions or for anyone to tell me what I may have done wrong to not be receiving power.