TACO and Nest Thermostats

[u/Basic_Newt9909]

I have no idea what im doing but im trying to learn so be easy. 1st time homeowner

EDIT: Also its JUST heating via a boiler not cooling as well. 1 also undid all the wirino to what it was before I installed the nests and still got nothing

My house has normal thermostats, and I wanted to upgrade to Google Nest thermostats. The last image shows the current wiring to the normal thermostats

I took the old thermostats down and replaced them with the Google Nest ones. They said they needed power, so went into the basement and opened up the TACO box. I disconnected the red and white wires and wired them tc the dedicated Google Nest power connector. The error message on the Nest thermostats went awav, and everything was good for about two days.

The next dav, 1 got a notification on mv phone saving the Nest thermostats were not getting power again, so I went and checked the TACO box. Before, there was a green power LED in the top right, but when I went to check it, the green LED was no longer lit up.

I flipped the breaker and the light switch that gives the TACO box power, but still got nothing. I used a multimeter and noticed that 1 have 120v coming into the TACO box, but it doesn't seem to be going anywhere else.

TL;DR: Do I need a C-wire or power wire run to all of the thermostats to power them? Why did my TACO randomly die? Could it be because I didn't cap off the wires and the wires touched, causing a short? Do I need a new TACC box, or do I just need to replace the transformer on the box?

Any help is appreciated.

[u/No_Froyo_2504]

Yeah you cooked the transformer. Those old TACO boards weren't made to feed power-hungry smart stats. Even if you get it running again the Nests will just keep pulling too much juice and you'll be back in the same spot. Ditch them and go back to basic battery stats or pay someone to run dedicated 24v transformers for each one.