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Nest thermostat with Baxi caldaia murale – natural gas heater with Perri Termostati a 220 240v thermostat

12 Feb

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

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:

with_separate_power supply_dry_switch_eletronic_perry_TE120_TE121_TE122_TE123_termostati_elettronici

…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):

baci wiring as-is_inclusive of power supply_termostati_elettronici

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

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….

the futuristic nest thermostat 20130212

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?

map of nest thermostat location relative to gas heating system

16 Jan

Good evening to all,

I said in my previous post, since we have been talking a lot about wiring and electrical aspects…

at some point comes the “routing” of all those connections. Below you can see if my apartment and

the three key area of interest: the heating system location, the breakers box and last but not least my nest thermostat location.

A couple of comments:

  • all rooms are fitted with cast iron radiator
  • each cast iron radiator is fitted with a thermostatic head to the exception of the so-called “Bedroom 2” where the thermostat is located (for obvious reason)

the idea is to regulate the coldest room to whatever temperature I need and let all the other room (warmer in general) get settled via their individual thermostatic heads.

All I can say even before the Nest this setup worked pretty well – but the smartness of Nest is likely still to bring energy savings (hence dollars, Euros or whatever your currency is – I am flexible). the only issue I know with this setup, I will likely have is the auto-away feature not working well given the location of the thermostat (comments are welcome as usual).

nest thermostat appartment

Current plan:

– to wire my nest thermostat to the breaker box where the Aube RC840 unit will be located (this requires 3 wires, W/R/C)

– wire the aube RC840 to the Gas heater (this requires also 3 wires Ns/Ls/Lr).

Alternative plan:

– I may place my Aube RC840 right next to the gas heater (in case I struggle to add an extra wire – see my previous post)

– route W/R/C wires to the “breaker box” and then dispatch them to the nest location by means of proper “jumpers”

wiring nest thermostat aube rc840 heating system

I have full flexibility when it comes to the number of wires to be run from the green box (the breaker’s box)

to the Nest Thermostat, however, I am missing 1-wire from the green box (the breaker’s box) to the gas heating system (blue).

As a side comment, a Neutral/Line/Earth are also needed to supply the Gas heating system (hence the 6 wires needed)

talk to you guys soon, any feedback? questions? critics? candid feedback is always welcome!

electrical schematic of nest thermostat with 220 240 volts heating system

19 Dec

nest thermostat 220v europe

nest thermostat wired to a 220V heating system

following request for clarification,

here is my understanding of how this works, and particularly what is the RC840-240T doing for you.

#1 RC840T-240T is overkill – this box is designed to drive directly an electric heater (2kW or so…). this means the relay in this box can carry a lot of current

#2 note this device is not approved in Europe, probably because of 50Hz and 220 240 Volts (versus 60Hz and 110 Volts), so a new certification would be required.

#3 and I Will pause here, I have a doubt about the need (or not) for the C wire to be connected honestly, so I will investigate and report back once I have a chance to spend more time.

the natural gas heater and its nest access

17 Dec

my heater is a basic elm leblanc acleis 23kw natural gas.
it works on 220 240 volts and is currently trigger by a 2-wire high voltage thermostat.

here is the front of the heater

20121217-223729.jpg

with the cover removed

20121217-223803.jpg

the Aube/ RC840 box will connect instead of the grey and black wires.
those are precisely hooked to Ls and Lr connectors.

it is worth noting that I will leverage from the Ns connector which on a high voltage 2 wire thermostat is not used.

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