Can you program the fan to work only for secondary heat & AC

[Kanner6]

I have a system which the primary heat is radiant base board heat.  If the Base board heat cannot keep up the secondary heat is ran from a Transom unit which also has the AC and Fan.  I need to program the nest to only operate the fan when Transom unit (secondary heat) is required, and for AC.  No reason to operate fan for Radiant Heat (Primary heat)  Is this possible?

Wiring - Primary heat to W1 - Transom Heat (Secondary) to W2/Aux - Transom Fan to G - Transom AC to Y1

[zoeuvre]

Hi Kanner6, 

Thanks for posting here in the Community forum. The system you have is equipped with both primary radiant baseboard heat and a secondary transom unit for heating or cooling. To program your Nest Thermostat to only operate the fan when the transom unit is needed, you can follow these steps:

1. On your thermostat, go to Settings.
2. Look for the fan settings in the Nest thermostat's configuration menu. You may find an option called "Fan Control" or "Fan Schedule." Select this option to customize the fan operation.
3. Within the fan settings, you should see options to enable or disable the fan based on specific conditions. Look for an option that allows you to activate the fan when the system is in heating or cooling mode, and disable it when the system is in radiant baseboard heat mode. You may need to select "Heat Only" or "Cool Only" for fan operation, depending on the available options.
4. Depending on the available settings, you may be able to set specific temperature thresholds or schedules for the fan operation. Configure the fan to activate only when the temperature reaches a level that requires the transom unit for heating or cooling.
5. Once you have configured the fan settings, test the system to ensure that the fan operates as desired. Monitor its behavior during both radiant baseboard heating and transom heat or cooling to confirm that the fan activates only when necessary.

Let us know how that works.

Best,

Zoe

[Kanner6]

Sorry for confusion, I did not have the nest thermostat in front of me and was asking blind.  So now, little more information, I have a nest 1st generation, which has Y, C, W, G, R and *OB line.   I have the nest connected through my phone and I am looking at setup options, I do not see any fan setup options nor do I see any way of programming the equipment for a second stage.  Do I have the wrong thermostat for my needs.

[Jenelyn_O]

Hi folks,

Chiming in — it looks like you have the Nest Thermostat 2020, the mirror one. Checking your thermostat's Equipment, Wiring, and System Details in the Google Home app under your thermostat's Settings might help. 

Equipment

The options or settings available in this section depend on what type of system you have. (Example: If you don't have an auxiliary heat or emergency heat, the Auxiliary heat lockout or Emergency heat doesn't appear under Equipment. If you have a humidifier, a Humidifier setting appears.)

Wiring

When you tap Wiring, you can check their thermostat's wiring configuration and tap Update wiring if you need to make any changes.

System details

In this section, you can check the summary of your system information or configuration. If you want to make changes to the settings, you can go to Equipment and tap the option you need to update. 

Please let me know how it goes. 

I appreciate your input, Zoe.

Regards,

Jenelyn