thermostat compatability with my current wiring picture

[letolkki]

Would like to replace with nest learning thermostat. Is OT1 and OT2 incompatible with the Nest Learning thermostat?

[letolkki]

I would like to replace the thermostat with a nest learning thermostat. Does OT1 and OT2 in the picture above make it incompatible? I have an Oil furnace with a heat pump/AC unit that switches at over to heat pump when temps are above 35.

[ctcomsa]

no i believe it will work they just connect to the heat link on a nest thermostat E 

this should explain it more.

https://support.google.com/googlenest/answer/9247634?hl=en-GB 

[letolkki]

Thank you for the link. Is the nest thermostat E and the Nest learning thermostat the same in that they both have heat link?

[Patrick_Caezza]

The OT1 and OT2 terminals are for an outdoor temperature sensor. They have nothing to do with a Heat Link. Do you even have a Heat Link? Heat Links are only available in the UK

[letolkki]

I was replying to ctcomsa above. I was ignorant to what a Heat Link was.

[MelbaDT]

Hey folks, 

Thanks for taking care of this, Patrick_Caezza. I also appreciate your response, ctcomsa. 

letolkki, I hope you got the answer you're looking for. As for dual fuel systems like yours, you will need to have a trained professional set up your thermostat. They will need to assess the requirements for your specific dual fuel configuration since choosing incorrect options for a dual fuel system can result in damage to your system. Contact a local pro for more information. 

Best, 

Melba

[MelbaDT]

Hey letolkki, 

Checking back in should you have further questions about this. 

Best, 

Melba

[MelbaDT]

Hi, 

We haven't heard from you in a while so we'll be locking this thread if there is no update within the day. If you have any new issues, updates or just a discussion topic, feel free to start a new thread in the community.

Best, 

Melba

[Patrick_Caezza]

The OT1 and OT2 terminals are for an outdoor temperature sensor which the Nest doesn't use.

Give this wiring a try

Red - R to Rc

White - W1 to W2 (set as AUX heat)

Yellow - Y1 to Y1

Green - G to G

Orange - O to OB

Blue - B to C

[letolkki]

If the Nest doesn't use the OT1 or OT2 how does it tell the system to switch from fuel (oil in my case) to heat pump when the outside temperature reaches threshold?