Hi there!
I’m a new user, recently took delivery of a built Touch v6.0 (I meant to get a kit, but I must’ve mis-clicked 
).
The device booted up brilliantly, I had no trouble connecting it to WiFi & openHAB on my phone, but I’m yet to connect it to my boiler.
I’ve spent an hour or so searching the hestiapi.com and this forum for a wiring schematic, but the only documentation I can find for installation is for installing software, or installing the pcb/screen into a case. I want to wire it to my boiler. Others have asked for help replacing existing thermostats, so I can try to reverse engineer instructions in other threads to see if they apply to my boiler too, but I’m wondering if I’m missing something obvious.
Is there any documentation that describes a standard physical wiring case, a schematic of the Touch v6.0’s output, or a specification detailing the behaviour of the device, to assist anyone completing wiring/installation to a boiler?
I’m assuming that when the HestiaPi Touch v6.0 calls for heat or hot water, 220v (or whatever supply voltage is applied to the AC-L terminal) is connected by the relay to the Heat or Water output. Is that right?
I’m guessing I’ve missed something obvious (apologies if I have). Does such documentation exist?
Thanks for your help, and the hard work of everyone who’s made this fab little thing a reality!
Jon
p.s. My boiler never had a thermostat installed (Vaillant Turbomax 824E, if you’re interested), so rather than install new wires, I’m considering adding an ESP8266 controlled 240v relay in the boiler cabinet (in my kitchen, not a great place for the central heating thermostat), which HestiaPi triggers remotely from a living area. One step at a time though!
Hi Jon,
the wiring diagram is indeed “missing”. Once we get the campaign started we will finalise the user manual which will be included in paper format in all orders from now on and of course will be available on github too. It will include schematic and wiring diagram to help people.
In words, the AC L and N need mains L and N as you have already done.
When heating is turned on, the H terminal will be connected to L to return mains voltage to the furnace.
But if you don’t have wiring to your furnace and you trust your WiFi connectivity, we would suggest to ditch the wires all together and install what you said.
The easiest solution would be a Sonoff Basic flashed with Tasmota firmware connected to the furnace input contact (that would travel through wires to the thermostat) that would listen to MQTT messages from Hestia.
If you can get the firmware in and the connections as described, the MQTT functionality is already there, supported and tested for many releases now, including the one you got.
Let us know if you need more info in any of the above mentioned areas…
Ah, ok, I get it. I hadn’t realised what stage you were at - apologies. Your explanations are super informative, thank you.
This is the first time I’ve jumped into an open source project like this, and it’s a steep learning curve. Exciting though! I’ve limited understanding of how it all fits together. I do have some exposure to microcontroller & python programming in a past engineering life, but new to this ecosystem & the scale of it - I’m enjoying learning. I got the hestia touch controlling my boiler in a test setup (I asked the question cause I wasn’t sure if I’d end up blowing something up with mains voltage!) and I’ve worked out how to get two devices sharing messages using MQTT.
I’ve found references to mosquitto in the github source, so I think I’m slowly piecing it together, and a search for mqtt in this forum has been instructive. I know now I need to learn about Bindings and Things in OpenHab (which seems well documented), then understand how to use the MQTT binding to work with the topics and messages I find searching MQTT/mosquitto in the repository’s code. Does it sound like I’m on the right track?
I’ve got a couple of devices set up as a test bed to understand how it all works now, and I’ll flash Tasmota onto the Basic once I’ve found my TTL adaptor…
Do you think reading up on MQTT in OpenHab docs is a good way to understand how it’s implemented in this project, or would you recommend some other source?
Absolutely! 
Keep in mind we currently use MQTT version 1 in OpenHAB. We are in the process of migrating to MQTT2 soon though 
which be 3-4 lines change for each additional topic you create copy-paste style. For the native topics, you won’t have to do anything.