adding outside wood fired boiler as primary heat source

[wtidball]

We have a 3 years old home with 2 HVAC forced air systems with electric heat running 2 Google Nest gen 3 thermostats.    We're adding a HeatMaster outside wood boiler system to our home and some outbuildings using heat exchangers in the HVAC duct work.      The HeatMaster controls the water tempatures and does NOT need or use any signaling from the house.   It constantly provides hot water at a set temp to the heat exchangers in each hvac system. 

The desired behaviour from the Nest thermostate would be to treat the boiler heat as heat source 1,  and the electric heat to be treated as a backup , or heat source 2.        We simply want to have the Nest turn the HVAC fan on or off depeding on the need for the heat thermostat set point for heat source 1  (say 70 degrees).    If the fan is on,  and the tempature falls below thermostate set point for heat source 2 (say 65 degrees),  then start the HVAC eletric heat on.

Can this be accomplished with Nest and if so,  can someone point me in the right direction?

[GabrielaG]

Hi @wtidball,

Thank you for reaching out to the Google Nest Community. I understand you are installing a HeatMaster wood boiler (Heat Source 1) using heat exchangers and an electric furnace (Heat Source 2/Backup). You want the Nest Thermostat to run the fan only below the primary set point of 70° and only turn on the electric heat if the fan is active and the temperature falls below the backup set point of 65°. I'm glad to help you.

To provide the best assistance, could you please tell me:

• Where are you located?
• Have you tried to connect the Nest Thermostat to the HeatMaster?

I look forward to your response.

Regards,

Gabriela

[wtidball]

Hey Gabriela,    Thanks for the response.      We're located in Topeka KS.         The HeatMaster has no outside hookups.   It has it's own controll board and manages the water heat and circulating pumps based on inlet and outlet water tempature,  outside tempatures and since it is heating multiple buildings is indepenant of any building.

[GabrielaG]

Hi @wtidball,

I appreciate the quick response and the information about your HeatMaster system and location. I am ready to continue assisting you.

To ensure I can provide the best assistance, could you please send me clear photos of the current wiring at both the Nest Learning Thermostat and the HeatMaster unit?

I look forward to your response.

Regards,

Gabriela

[wtidball]

Hi Gabriela,    Attached is the nest picture you requested and as I have mentioned before…….   There is no control needed at the Heatmaster.  Only thing it requires is 110 ac.   The Heatmaster is self contained and requires nothing from the thermostat.    Thanks