Nest Thermostat E with TACO ZVC406-EXP zone valve

[KapDAS]

I have a TACO ZVC406-EXP zone valve controller and want to upgrade my current thermostats with Nest E.  I have 2 wires running to the thermostat RC and W.  When i switch them out with the nest E, i have nothing at all, the thermostat will not power on.  Can anyone help me figure this out?

[Markjosephp]

Hello KapDAS,

Thank you for taking the time to let us know about your inquiry. I'd be happy to take a look at this for you.

It's possible that the Nest Thermostat's battery is dead because it was locked in storage for a long period of time, or this might be a power-related issue. Please try charging its display for an hour using a micro USB charger and wait until the screen turns on. After an hour, plug it back in on its base and ensure that all wires are properly connected.

Let me know if that helps.

Regards,
Mark

[Markjosephp]

Hey there,

I'm checking back in. Were you able to do the steps above? I'd be glad to hear from you — I'd like to make sure everything is working.

Thanks,

Mark

[KapDAS]

Hi Mark,

It did not work, apparently the TACO system does not have enough power to feed the thermostats.  I am setting up 5 new thermostats and the board cannot support more than 2.  I have ordered a 24vac external transformer and will try setting it up later today.  I will keep you posted once i have installed the transformer.

Thank you,

Paul.

[zoeuvre]

Hi folks,

@KapDAS, thanks for reaching out to us and for showing interest in our Nest Thermostats.

Even though they may say they are compatible with the Nest Thermostat, some C wire adapters from third parties can malfunction or harm your Nest Thermostat. For optimal performance and compatibility with your thermostat, we advise utilizing a Nest Power Connector.

Let us know if you have any other questions. We're happy to help. 

I appreciate your assistance here, Mark. 

Best,

Zoe

[Jenelyn_O]

Hey KapDAS,

I wanted to follow up if you still need help. Please let me know if you’re still having any concerns or questions from here, as I would be happy to take a closer look and assist you further.

I appreciate your help, Mark and Zoe.

Thanks,

Jenelyn

[Jenelyn_O]

Hi there,

Due to inactivity, we'll go ahead and lock this thread in 24 hours. We'd be glad to help you further so if you still need assistance, feel free to start a new thread.

Regards,

Jenelyn

[KapDAS]

Hi Jenelyn,

I do require some more help, we installed the external transformer to the nest thermostats, all 5 of them.  They are all powered on and sufficient power running to them.   I have 3 wires going to my thermostats.  R,W & C.  R and C are currently plugged directly to the thermostats from the transformer without going to the TACO zone controller.  Only W is plugged from the Taco to the thermostats.  How would i wire the thermostats to the taco to work?  I tried uploading a picture but i don't seem to be able to.

[Jenelyn_O]

Hey KapDAS,

Please try to click this link then scroll down to your response and hit reply. Check for the camera icon or click the three horizontal dots to expand the toolbar. From there, you'll be able to reply and share a photo.

Kind regards,

Jenelyn

[zoeuvre]

Hi there, 

I want to check and see if you are still in need of any help. Please let me know, as I would be happy to assist and answer any questions you may have.
 

Thanks,

Zoe

[Dan_A]

Hello again,

It's been a few days since your last reply — we're going to lock the thread within 24 hours. If you have further concerns, please feel free to create a new post.

Kind regards,

Dan