edited on Feb 12th 2013 – futuristic views included
following a request from Massimo a Nest thermostat potential adopter in Italy,
I am trying to assist him in what could be the ad-hoc wiring of a Baxi gast heater mated to a Perri Termostati, a 220 240 thermostat.
the two thermostat wiring options are shown below:
- perry thermostat TE120 TE121 TE122 TE123
elettronic termostati perry italia
in my opinion, the “red” boxed wiring (if compatible with the Baxi heating unit) is preferred.
Massimo having now confirmed his wiring is not the red box above, but rather the separate circuitry of supply and dry switch as shown below:
…I am starting to think about how is the actual wiring done at the heating unit level – my point being that I do not believe the actual wiring per Massimo’s feedback
is as shown below (from the Baci user manual):
section added on Feb 12th 2013.
so given the status reach previously, here is below what I would advise one may want to setup in order to make the Nest Thermostat work with a heating system not providing both line and neutral.
Please note that my preliminary conclusions are that the RC840T is not per-say compatible as-is.
baci thermostat nest wiring prosposed
Now if we want to get a notch more futuristic and ask Nest Lab a serious ease of implementation with “most” heating systems in EU (at least the ones working on 220 240 volts), here is what a good step forward would be….
I just want to point that this version of Nest thermostat does not appear to exist today, but it should not be that complicated to roll out for the European market.
what do you think? Do you concur?
using nest thermostat in Europe... (on a 220V system) 
No.My Perry thermostat is wired as in non red box. ( the first figure).
I think that 220v wires in aube is 220 v wires in perry thermostat( wires red and black in your figure) and the blue wires is wire 4 in perry thermostat. What do you think? Thanks Matt.
Don’t have any advice for me?
ok thanks , i wait
Hi, did you make the circuit? I have my nest working in the UK with a circuit I made to work in place of my 220V thermostat. Do you need help?
Danny,
if you happen to have a solution for Massimo, would you please be able to share your schematic?
please also help us understand your heating unit brand, configuration etc…
I am happy to draw your feedback in an electronic format for everyone’s benefit.
I am currently lacking of time to respond promptly.
thank you
I need help. Yes.
I’m waiting for your response
Help please!
Hey any news for me?
Massimo,
I will propose something tonight… but i am worried there may not be any real solution in the short term, until Nest proposes something slightly different in terms of wiring.
Matthieu
Ok. And so i will try your porposed wired.
I wish that your advice will be realized
hey but aube 240 have only 3 wire in 220 v in (blue,red,black) ,but you have drawn 4(blue,red 1,red 2,black )! what can i do?
sorry mat and so, i can’t use aube?
i will use aube and othe transformer 220-24 vac?
unfortunately, yes Massimo – it occurs to me you need completely separate 24V transformer to the switch/relay itself. Aube product does not support this I am afraid.
if I was to identify a product doing the job, I would keep you posted.
Hallo, I live in Italy, so I had to do some trick to connect Nest to my home, but I can’t get it work…
I bought a transformer (from 220VAC to 24V alternate current) and connected it to the C and Rh of Nest; then I would use the W1 wire to feed (together with a a splitted wire from C) a relais (always 24Vac); the pure contact of the relais may command my gas equipment.
Now, from the W1 I always get a 24V, even if I set my Nest to lowest temperature.
May someone help, please?
I have exactly your same issue.. did you manage to fix it? thanks!
Nope, it seems that my Nest is defective, as many users managed to connect just this way. After some time, it refuses to turn on, and I had no support as I was living out of the US.
But the magic of the Nest is just a particular function called PID; this is what auto-tunes thermostat. Nest is not the only one to have it, but it’s the most expensive…
I live in Italy and have Perry Thermostats in the house I rent. According to specs sheet they operate with 230V. Will I be able to install & use properly a nest thermostat ? I have infloor heating with gas.