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Bosch Wifi Thermostat Wiring Help.

Dan M
4 years ago

Hello Everyone. I have a Bosch bcc100 smart thermostat and a 13 year old Carrier furnace and central air unit. When the AC kicks on, it sounds like the blower starts, then there’s a big “clunk” sound, the thermostat clicks, and then the AC compressor turns on. I’m not sure why this happens, and I don’t know if I have it wired incorrectly. If I switch back to my old digital thermostat, the AC operation is smooth. Any help would be appreciated.

Below is how I wired the Bosch smart thermostat. Just an FYI…I’ve tried both Rh and Rc with the same results. Is the jumper causing a problem?

This is how my old thermostat is wired.

This is how the furnace is wired. It’s hard to see, so I’ll try to explain. The C terminal has the blue wire going to the thermostat, and two white wires, one from the AC and the other from the humidifier. The Y terminal has the yellow wire going to the thermostat and the red wire from the AC. The R, G, and W terminals have the red, green and white wires going to the thermostat.

Thanks for any help!

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