Replacing White Rodgers 1F78 with Nest Learning Thermostat Gen3

[szewonkwok]

Hi there, 

I'm trying to replace my old thermostat. My current thermostat is White Rodgers 1F78, and the replacement model is the Nest Wifi Smart Learning Thermostat Gen3. However, I'm not quite sure how should I connect the wire properly, also there's no C wire connected to the old thermostat. I attached a photo to show the wire connection. It would be appreciated if anyone could provide more information about the wire connection. 

Thank you!

[Patrick_Caezza]

@szewonkwok 

Just match the terminal labels on the original thermostat to the label on the Nest. You can ignore the jumper between RC and RH, as the thermostat will internally make the connection if one is needed.

The Learning Thermostat can operate just fine without a C wire, but I always recommend installing one. You can use a spare wire if there is one or use the Nest Power Connector.

[szewonkwok]

Hi @Patrick_Caezza! Thank you for your reply! I have one more question, should I plug Y into Y1 or Y2, and for W should I connect to W1 or W2? 

Thank you!

[Patrick_Caezza]

@szewonkwok  Use Y1 and W1

[szewonkwok]

@Patrick_Caezza  Got it! Thank you so much XD