Hi
I am looking for a wifi switch (on/off) to use it with HA for my water heater. The problem is that I can not make a hole in the wall so I need it to be attached in the wall (I don’t know the English word for this)
I will attach it above of my thermostat
I need it to be attached like the thermostat (no hole)
I could use something like this but they don’t have an extra frame in order to be attached in the wall and to hide the wires behind.
Do you have any suggestions ?
(I hope that it makes sense what I just wrote 
)
I was going to suggest a sonoff basic, but you need the wires hidden.
Yes hidden, because it will be with all the others switches in the hallway wall
Why dont u just rewire it. Meaning connecting your wires trough en place a sonoff switch somewhere you don’t see it?.
I sorta did the same in my case. Only i used a relay to switch my thermostat. The idea is the same which you’re seeking. You want to operate your thermostat trough Home Assistant. And reading your post it seems you got a On/Off function on your boiler, meaning it can work.
Well this could be a solution. The only place it could be installed is at the electrical panel which is also in the hallway. I am not sure although that it could fit (space i and the other problem is that it will be also view-able.
Is there a sonoff device I could alternatively use?
There is a sonoff mini. But I think there will be a space issue as well. I can’t think of anything else
I need a little help to understand the wiring (although I am not going to install it - a professional will)
Right now we have 3 wires - Live,Neutral, and the one that will give the order to open the wifi heater.
This is how my electrician describe them.
How can we connect them to sonoff basic or mini? Do I need another sonoff switch?
Wiring isn’t that hard if you know what you’re doing
the wiring depends on what else the signal is switching. Because if I understand correctly you’re still using your normal switch thingie to switch it on or off. You need to get rid of it completely to let the sonoff work. And then I would say, connect it to the signal and ground wire. But you can troubleshoot a little bit with it.
I will let the electrician to think about it. I hope that he can do it
After a discussion with my electrician we will use the thermostat for heating the house and with an sonoff basic (hided behind the electrical panel) and a relay I will have access to water heating.
There is one more option that I could use a sonoff basic R3 which decent enough to be seen below my thermostat