Nest thermostat install in 2 wire system with 3 zones

[MPH0229]

Looking to install 3 Nest thermostats in a home with 3 zones and no c wire. The Taco relay/zone control panel has individual thermostat wire connections for each zone. Do I need 3 Nest power connectors to make this work? This is my daughters home and she had previously purchased the thermostats and has missed the return window to get a different WIFI thermostat.

Thanks in advance

[Patrick_Caezza]

@MPH0229 

Can you post a picture of the Taco valve zone controller?

There is a good chance you will need three Power Connectors and an external 24vac transformer.

[MPH0229]

Hello Patrick and thank you for the advice. I have a photo but I cannot seems to find to how to post it to this platform. There is a 24v transformer in the zone controller although none of the T.stat wires go to it.

Mike

[EduardoN]

Hi @MPH0229,

I appreciate the information you shared. Based on my understanding, I'd like to ask some further questions. I'll also provide some additional details.

• Is your system for heating, cooling, or both?
• What wires are connected to each zone?
• What type of Nest Thermsotats do you have?
• Does your system use gas, oil, propane, or electricity?"

@Patrick_Caezza, thanks for sharing this information, it's great for all.

Please feel free to share any additional details you think might be relevant.

Best regards,

Eduardo

[MPH0229]

This is a heat only system which is gas fired. Each zone has the red and white wire connected and the thermostat is the basic nest thermostat not the E series.

[EduardoN · Accepted solution]

Hi @MPH0229,

Thank you for sharing this information about this situation. To ensure consistent power to your Nest Thermostats and prevent any further issues, it's best to use one Nest Power Connector for each zone in your house. Nest Power Connectors regulate power flow and can resolve many common power-related problems that might cause your thermostat to go offline or malfunction.

Keep me post.

Best regards,

Eduardo

[Patrick_Caezza]

@MPH0229 

This is how you post a picture.

[MPH0229]

Patrick,

For some reason the only way I can get this picture that my daughter sent to load is via a link.

Mike

https://mail-attachment.googleusercontent.com/attachment/u/0/?ui=2&ik=0d1642c3f1&attid=0.1&permmsgid... 

[MPH0229]

@Patrick_Caezza

Back to my daughter home and ready to get things installed. This link will open a picture of the zone control valve,

 https://mail-attachment.googleusercontent.com/attachment/u/0/?ui=2&ik=0d1642c3f1&attid=0.1&permmsgid...

[EduardoN]

Hi @MPH0229,

It appears the Recommended Answer has worked for most people experiencing this behavior. Please let me know if you have checked that information for your installation.

Best regards,

Eduardo

[MPH0229]

Eduardo,

I have installed 2 Nest Power Connectors and installed 2 thermostat and have powered them(C) wire of of the Common lead in the Taco zone control unit and it will only power one thermostat. Do I need a larger transformer if am going to power three  Nest Power Connectors?

[MPH0229]

 

[Patrick_Caezza]

@MPH0229 

Sorry for the late reply, it's been rather busy here for me.

The Taco Valve controller can't provide enough power for itself and the new thermostats.

You are going to need an external 24vac transformer and you can wire it like this for each zone. You can use just one transformer for both Power Connectors.