BTW, I just committed a page describing the pins on the front panel to make it easer connecting esp devices. navien/doc/240-a.md at fe98306a94e1c395a75fc0f4a24979b280c23af9 · htumanyan/navien · GitHub
I’m definitely interested in the custom hardware. Thanks!
Here is how the device looks like. It has two leds indicating the status of Wi-Fi connection and the RS485 to Navien.
It comes with a custom wiring harness for plug-and-play connectivity to Navien-240a. It can be modified for other Navien models also.
It can work off of a USB charging brick connected over micro-usb connector on the side or fed from the Navien-240a internal power supply (I like the latter to avoid extra wires). The micro-usb connector can be also used for flashing the new versions (of course, the normal esphome ota works too).
I’m interested in the custom unit too. Nice work!
Interested in a unit as well. Very extensive project. Looking at purchasing a new boiler and this project is pushing me to Navian. They should give you a commission!!
Thanks to folks on here I got a script running on my Raspberry Pi to pull telemetry from the heater. Since I got a lot from here I figured I contribute pack a little - I figured out a few more pieces of information:
navien_ha/readme.md at main · ificator/navien_ha
The most interesting is the total water usage, but there are a few other pieces in there as well.
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Sorry if that was for me. I’m bad about noticing the UI flag.
Thanks for everyone’s work on this. I just recently picked up a 240S2 for my shop and looking to add some telemetry to it along with other building automation.
@htumanyan I’m looking into using the Norvi Agent1 ( Industrial IoT Node Agent One | Modbus-MQTT Controller ) because it supports RS485 out of the box as well as having a few other 0-20ma analog sensor inputs. My goal was to use it to read from the navien as well as read water pressure sensors on either side of a filtration set up. I have found an esphome yaml for the Norvi IIOT here. Do you think it would be that difficult to modify your navien esphome to work as a general “water information” module? I haven’t yet decided if I will be using home assistant or some kind of custom SCADA. I suppose it is just as easy to reconfigure home assistant to work as “building assistant.” 
Thanks everyone!
Hello, here is how, I think, you can make the IOT device work:
a. Copy the configuration yaml, you’ve linked into the same folder as other yaml files in the repository
b. Add substitutions: and packages: sections to that file just like it is done in navien/esphome/navien-esphome-atom-lite-esp32.yml at 0cce0008a8e2653a7d5eab1716aae34d7121bfd7 · htumanyan/navien · GitHub or any other yaml files in that folder
c. Ensure that tx_pin, rx_pin and other values match what you see in your board configuration.
In the simplest form you can even just copy the navien/esphome/navien-esphome-atom-lite-esp32.yml at 0cce0008a8e2653a7d5eab1716aae34d7121bfd7 · htumanyan/navien · GitHub and update rx_pin/tx_pin - that should yield a working baseline.
I would like to buy your Navien custom device. How to do so?
I’ve sent you a private message, Ed.
I’d be interested in a custom device as well. Thanks.
Hello, I would like one of these units. I have a Navien NCB-180E.
I am very interested in your device! Thank you for all the work on this!
@htumanyan I would be interested in this controller device (would need two actually!)
Did you get this setup to work? I’m about to get two units installed in a cascade arrangement…