Google Nest Power Connector - C Wire Adapter for Smart Thermostats - 3.98in Accessory, Snow

Of the 3 thermostats I replaced with google Nest units in my house, the 2nd floor one I could not pull out and replace the old 2-wire R/W cable. (Two 1st floor thermostat locations I replaced with 3-wire cable). This Power Connector cleverly solves the problem. Attached near boiler controller in basement, it converst the W function of a 2 wire to a C (common) function. That ensures 24V continuous power to keep thermostat continuously up and running. The W function is done by superimposing a signal whereby the Power Connnector implements the R/W relay closure and opening.Be sure that your controller for your heating system has a "C" Terminal- many older (pre 2000) systems don't. If it does not, likely its transformer may be under powered for operting smart thermostats. There are electronics solutions available to augement older controllers to support smart thermostats. (I bought one made by Argo).

I didn’t know my nest thermostat was not receiving power and on battery until it was too late. My thermostat shutdown and required manual charge on a 92 degree CA day.I installed this little device in less than 10 min. Up and running and in not time my thermostat was a full 3.85 volts and holding (before it would tick down a hundredth a day).

Something is wrong with the Nest Power Connector's internal components, as it tries to deliver power. I'm not sure how it's supposed to work (some kind of switch?), but it does not do the same job as a dedicated C-wire. To preface, we have a baseboard radiator system with an oil furnace and a separate AC system with air handlers. Some thermostats in our house are heat only, others both AC and heat.I installed two Nest Power Connectors, one on a Nest Learning Thermostat 3rd gen and one on a Nest Thermostat. Installation was a breeze. The 3rd gen had previously been using the workaround with a G (fan) wire as a C wire with no power issues. The Nest Thermostat was newly installed. After installation, the Power Connector at the air handler for the Nest Learning Thermostat (heat and ac controller), the unit started having low power issues within 24h (screen not turning on, disconnecting from the temp sensor, wifi disconnecting). Same issue with the Nest Thermostat in the basement (heat only) with the power connector at the HVAC (a Taco 6 zone switch relay board), with power issue error messages showing up on the screen and being emailed within a week. I double checked all the connections with a multimeter, R to W and R to C both had ~27 V, and the Nest itself read enough power coming in.Unfortunately, I had to remove the devices and run a dedicated C wire (not an easy process in our house). Since installation of the C wire, the Nest Learning Thermostat has been working excellently with no issues, indicating that the Power Connector does not do its job as a replacement for an actual C wire. (The other Nest Thermostat still will not work as after a week it had another power issue, and Google Nest support did issue me a replacement device. So it's hard to judge what caused its failure.)

Installed a Nest thermostat on my daughter’s condo and found out she only had two wires, red and white with no possibility of running a real C wire due to plaster walls. Confirmed that the furnace had a C wire (critical) and then ordered this dongle. My application was a heat only furnace so the wiring was fairly simple.I strongly recommend that you get three of the wagu type snap-on UL approved wiring connectors unless you have screw terminations to attach to. There are two of the snap on connectors in the box but you will need three more for the furnace side . Trust me - have the connectors handy and installing this device is easy, I tried to use twist on wire nuts but the nuts would no stay on.You need to “tell” the nest thermostat that this adapter was installed during the programming phase on your phone or tablet. Do that slowly because if you miss the check box that says this device was installed the thermostat will not work and the only way to fix it is to delete the thermostat and install it as a new device.Note - This device is specifically designed for the nest thermostat. It will not work as a workaround to add a missing C wire to other thermostat brands.

The Nest power connector worked just like it was supposed to and solved my issue. The only downside was the wire connectors it came with, they didn’t hold the wires tight and felt loose. I ended up using regular wire nuts instead.

Bought a nest from my power company for dirt cheap ($15) as part of a green initiative program. Was disappointed when because I don’t have a C-Wire I would get a low battery alert after only a few weeks and also an error code that would never go away. WiFi would disable once the battery was low also. This was an incredibly easy part to install. The hardest part was figuring out where to mount it so I could put the cover back on the furnace power unit that is mounted in the wall. After I followed the easy instructions I put a pair of fresh batteries in the nest, turned the power back on and BAM no error code! I’m assuming batteries will also last much longer. It stinks I had to buy this unit that was actually more than I paid for the nest, but in the end it all worked out and was still relatively cheap!