QuestionsCategory: QuestionsWiFi Install no C Wire for thermostat or control panel
Handyman Staff asked 3 months ago

New home and trying to change old thermostat. New DIYer for electrical and HVAC. No C Wire however it does have 5 wires. RH, RC, Y, W, G.

Attached is the schematic on the actual unit. I am unsure how I would be able to wire a new thermostat without a C terminal. I have a Honeywell adapter coming in however I don’t know which wires to attach it to. Not having a control panel with terminals made this confusing.

The schematic shows only 4 wires but to my understanding and per the photos. RC and RH attach to the R line making it all one for the thermostat.

The white wire with 5 internal lines runs directly to the thermostat. The brown wire with red white and us used green come from outdoor unit.

Any help would be appreciated!

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