topic Re: Adding three nest power connector with three zone Taco in Nest Thermostats

Adding three nest power connector with three zone Taco

nest17 — Sun, 05 Mar 2023 20:42:36 GMT

I have three heat zones. There is no zone controller board. Each Nest thermostat (not learning and not E) is currently wired before the zone valves. Each thermostat has two wires going to it. The zone valves do not receive any power unless the Thermostats are on. (I verified this with a multimeter). How do I wire my power connectors to my system? The thermostat is powered by two 24v transformers.

Can I connect the power connector downstream from the Thermostat but before the zone valve?

Re: Adding three nest power connector with three zone Taco

Patrick_Caezza — Sun, 05 Mar 2023 04:03:07 GMT

Which Taco Valve Zone Control do you have installed?

How many wires are going to the thermostats?

Which Nest thermostats do you have?

I have read about using T1 on the valve terminal to supply the C wire connection, but by my understanding of the circuit, T1 only supplies common when the relay is energized, as you have found. I don't have access to a Taco controller, so I could never verify my thoughts as you have.

When I was looking at the circuit for a Zone Valve, it looked like the T2 terminal was connected to common all of the time. Check that out if you can.

If that isn't the case, you will have to use one leg of the 24Vac transformer output as the C terminal, or you can use an external 24Vac transformer and connect it like the following. You will only need one external transformer for all of your power connectors.

Step 6.D is only needed if you use an external 24Vac transformer.

Re: Adding three nest power connector with three zone Taco

nest17 — Sun, 05 Mar 2023 20:45:19 GMT

I have updated my original post. I have a Nest Thermostat (not E or learning). We have two wires going to the thermostat and no zone control boards.

Re: Adding three nest power connector with three zone Taco

nest17 — Sun, 05 Mar 2023 20:50:06 GMT

The zone is currently wire similar to the diagram called “typical wire diagram” in the bottom left of the PDF https://inspectapedia.com/heat/Taco-Zone-Valves-555-573-Manual.pdf

Re: Adding three nest power connector with three zone Taco

Patrick_Caezza — Sun, 05 Mar 2023 22:27:29 GMT

You must create a C wire when using a Google Nest Thermostat with a 2-wire heat-only system. The best way to create one is by using the Google Nest Power Connector and wiring it like the diagram I have attached below.

You will need a separate power connector for each thermostat, and you can connect the C terminal of the power connector to the white wire on the 24Vac transformer.

Re: Adding three nest power connector with three zone Taco

Jenelyn_O — Wed, 08 Mar 2023 19:43:13 GMT

Hi there,

Chiming in — I just wanted to know if you were able to install your Nest Power Connector, and followed the guide provided by Patrick_Caezza? Please let me know if you have any questions or concerns, as I'll be willing to assist you from here.

I appreciate your help, @Patrick_Caezza.

Best,

Jenelyn

Re: Adding three nest power connector with three zone Taco

nest17 — Thu, 09 Mar 2023 12:41:01 GMT

My question is slightly different. I am wondering if I could connect the Connector after the thermostat but before the valve, but that doesn't seem possible.

What would help is if someone could describe how it works. The thermostat draws power when it closes the circuit, but that also starts the heat. I am wondering if the Nest Thermostat or Connector does something clever like change the wattage. If the thermostat closes the circuit with a certain wattage, the connector will route the load to the heating system. If not, it will route it to the common.

Re: Adding three nest power connector with three zone Taco

zoeuvre — Sat, 15 Apr 2023 21:44:31 GMT

Hi nest17,

I wanted 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 for your help, Jenelyn.

Best,

Zoe

Re: Adding three nest power connector with three zone Taco

zoeuvre — Tue, 18 Apr 2023 22:43:05 GMT

Hey there,

Before I mark things as resolved, I wanted to check and see if there might be anything else you needed on this or to see if you had any other questions. If there's more you need, just let us know.

Thanks,

Zoe

Re: Adding three nest power connector with three zone Taco

zoeuvre — Thu, 20 Apr 2023 16:24:30 GMT

Hi folks,

We haven’t heard from you so, I'll go ahead and lock this thread within 24 hours. If you run into any more issues in the future, please feel free to create a new thread.

Regards
Zoe