Before I install my new Nest Learning Thermostat, I thought I'd check in with you all in case you've done it before yourself. It's an assumptions check more than anything. The first pic below (square plate with two rows of connectors) is the connector plate for my new HVAC system. The second pic below (round plate) is the Nest plate with which I'd like to replace the old one.
Three of the five wired connections seem pretty straightforward: the G, C, and R wires go right to their counterparts on the Nest plate. But the Yellow wire connecting into the legacy plate could go to the Y1 or Y2 connection on the Nest plate, and likewise there are W1 and W2 options on the Nest plate not included on the legacy plate. Should I just default to connecting the yellow wire to Y1 and the white wire to W1, or is it more complicated than that?
Upstairs I have a traditional thermostat controlling heat connected to this adapt a stat transformer relay. The relay connects to a 12/2 with just a black and white wire. This goes to an oil burner that for some reason is 120v. My downstairs heat is using an old mercury 120v thermostat.
The adapt a stat outputs 2 red wires that are manually labeled r and w connected to the thermostat.
On the opposite wall I have a traditional thermostat controlling my a/c.
Project was to consolidate to one thermostat, so tried pulling the 12/2 and adapt a stat to the attic and extending the r and w wires from the adapt a stat to the same thermostat as the a/c.
For some reason it isn’t working, I measure 20v on the r/w wires but not sure if the relay is working as when I connect the wires the heat does not turn on. Connecting the 120v black and white does turn the heat on.
Question: is the adapt a stat fried? I don’t have a neutral and I haven’t explored the wiring on the oil furnace yet. Can’t seem to find this adapter relay anywhere for sale. In the interim I connected a high voltage thermostat to the 120 v wires.
Any recommendations?
[img]https://cimg5.ibsrv.net/gimg/www.doityourselft.com-vbulletin/1500x2000/bb21bf4a_1e82_4c8c_a272_aab05990cb8a_b3d922e6f0427cb370150b9b62d70c194a543a56.jpeg[/img]
I have been look up some old post, thinking it is time for me to do the 24v conversion. while looking the old thread below, i have thinking. can I just replace the black wire on the boiler service switch line in? and connect red wire on the switch that i remove (black line in). sorry i have steal old post image.
thanks for advice
[img]https://cimg8.ibsrv.net/gimg/www.doityourselft.com-vbulletin/600x319/rc840_7d76b788252f02731a2782eae9ac57a1e438155f.jpg[/img]
[url]https://www.doityourself.com/forum/thermostatic-controls/574020-converting-line-voltage-24v-840t.html[/url]
12-15-21, 12:25 PM
