Thermostat C- Adaptor Help

Would someone be able to assist with the C-adaptor for this furnace/wiring? Note: at the furnace terminal, only Y, G, R are connected, W appears to be hardwired to other wire. Thx!!



Can you spread out the wires in the blower cavity? I can’t tell which wires are connected to which terminals with all the overlapping wires.

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Here you are. Thx!

This is a guess - your wiring is very non-standard, and doesn’t follow normal conventions, along with it being a bit of a rats nest in there. Without actually being there and the ability to test the wires, I can’t say for sure that these are the appropriate connections, but they are the only thing that makes sense to me.


Thanks! I’ll give it a try tomorrow, helping a friend. The only question would be how/where to wire the “W” if it’s not wired to the furnace terminal directly?

Don’t worry about it, follow the wiring diagram I posted. The green wire that is wirenutted to the white wire that comes from the thermostat goes up to control the hot water valve above, and the end switch built into the valve will power on the boiler or water heater or whatever is the source of the hot water for that radiator.


Done! And it works perfect!! Thank you @speadie