ST-2E to NCM-300 plus nest t-stat

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Closedguard10
Posts: 3
Joined: Mon Jan 24, 2022 12:34 pm

ST-2E to NCM-300 plus nest t-stat

Post by Closedguard10 »

Hello all, as thread title states I am looking to convert a ST-2E to a NCM-300 so I can install a Nest thermostat. The system is a 2-zone, forced hot air, natural gas system with AC. The panels look pretty identical, aside from the supply air sensor. Either way, I was curious what I would do with the "B" brown wire or "O" orange wire, as the Nest only has a O/B option and the ST-2E uses both. I provided a link below to show how the current panel is wired and a picture of the new one.
Also, if anyone has done this before, any tips or tricks would be greatly appreciated. Ive only changed panels like for like.
Thanks all!
https://imgur.com/a/Qfkzrpq
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