have verified in full my previously recommended wiring earlier this week – having a 3-wire (220 240 Volts) cable running from my gas heater, to my RC840, and 3-wire from my RC840 to my nest thermostat.
While doing this, I have actually used this to let me Nest get fully charged, updated to the latest software, and exercised it a bit.
A few comments for those who go thru this process:
- it took a few hours to get my nest battery charged up to at least 3.7V
- note that in between it may (at least mine did) reboot a few times – realizing it does not have enough energy to run wifi (required to get the update done – have no idea about the size of the download by the way, do you?)
- 3.7V is critical as it is the minimum Nest needs to be able to launch software updates
- once update was done, an easy trouble-free process, I was able to fully control my nest via my Ipad
I live in an 1930s building, and our apartment got renovated to the current Electricity standard a few years ago (meaning I have a decent amount of extra wires running thru the various electricity access). Frustration rose when I realize I did NOT have a 220 240 Volts with 6-wires but 5-wires!
This means I can’t properly wire the Ns/Ls/Lr from my heating unit to the RC840T (I had planned to locate it near my fuse box – opposite from my heating unit).
So I have paused my installation – and – it looks like the only alternative is to change the heater supply cable and upgrade it to a 6-wires one.That’s assuming of course, I have room to retrofit it!! If you can think of anything else to do… please chime in now!!
In any case, I have updated and confirmed now that the diagram below is fully working.
if you can’t figure out how is laid out the apartment and how the wiring has to run, I will draw up a schematic of the flat and the way the wire will be running thru.