Nest Thermostat - vacation home setting - hot water / heating

[carloria]

Dear community,

as the Pro Nest are too fare away from my place in Italy, I am seeking here for advice. The actual work will be done then by my local electrician - I am a DIY.

Goal: I want to install a Nest 3rd generation learning thermostat (not the thermostat E) including heat link to my old heater in a way that I can remotely turn on the central heating without having all the time hot water running (it is a vacation home so I will be often there not for a month or so - but some days before arriving I want to turn on the heating).

Location: Italy (North - so cold in the winter)
current setup:
oil fired heater with two switches (one is on/off the other one is summer(only hot water)/winter (hot water and heating) incl. an internal 30l water tank
heater has five cables (L, N, PE and two cables to/from the separate thermostat - see below) - there is the possibility to connect a sixth cable ("segnalatore di blocco" - "lock indicator")
separate thermostat on 240V (two cables to the central heater and two to an very old modem to switch the heater on/off over the phone)
The thermostat and the old modem will be taken away.
see pictures

Questions:
Preferable setup: how needs the heat link to be wired with the heater that via the Nest thermostat I can turn
a) the central heating AND hot water off, or
b) turn only the hot water on, or
c) turn the central heating AND hot water on
I guess in this case the switch on the heater would have to be on winter mode all the time

Alternative setup: how needs the heat link to be wired with the heater that via the Nest thermostat I can turn the central heating on and off but the hot water will be on all the time? If this is only possible, I will install the heater to a DECT power socket to switch on/off the whole system remotely.


Thanks a lot for any comments!

Carl

 

[EricMark]

You will get a page like this my details blanked, it should show weather as you can see raining today and if either system is running CH or DHW and clicking on the CH or DHW you can change the settings, so in my case DHW runs 5 days a week for 1/2 hour, the CH detects where my wife's and my phone are, and as we get close, auto switches on the heating if required.

My hot water is set on the computer, as to when it runs, I can't have central heating without hot water due to way the oil boiler is plumbed, but can have hot water without central heating, I have no tank thermostat and 1/2 hour is shortest time programmable, so I have found in summer 5 days a week keeps it hot enough, but this is down to how boiler is plumbed not Nest.