Navien, ESP32 Navilink interface

[iscraigh]

I have an older cr210A model. has anyone had any experience with this version? It does not seem compatible with the navilink lite controller.

Craig

[smurf12345 (Patrick)]

@dacarson, I wasn’t able to find 12v. I did find 5v on 1 pin, but the voltage dropped when trying to power the esp32 and didn’t work. I also found 24v when probing around, but the BUC I had only does up to 23v, so I’m just sticking with USB for power for now.

[jm1fd]

@dacarson

One more. In the Water packet, the Operating Capacity is:
id(uart_water_byte17).publish_state(bytes[17] / 10.0 / 2.0); // Sort of looks like GPM Operating Capacity (0 - 100%)

I have an NPE-180S2 and it does look like this byte is operating capacity for my unit, but at full tilt it is reporting 200% which is a simple fix.

[dacarson (David Carson)]

The board I am using can accept up to 32V:

• Supply voltage: 12 VDC (3.8V-32V)
  Where did you find the 24V?

[tabrisnet]

I find myself trying to hookup an NFB series boiler with NaviLink also to an ESP32.
Using a Y-connector for 8P8C/RJ45 & a MAX485 board.
Connecting to pins 4 & 5, tried reversing A&B, popped off the R7 resistor on one MAX485 board… everytime I connect it the boiler drops off from the Navilink [takes a minute, the mobile/cloud app crashes].
I’m not using the 12V/GND, the ESP is powered from USB.

I have disassembled the Y-connector, it looks that all pins/wires are connected.

I get that the wire protocol could be different from the NPE [I have one also], but I haven’t gotten that far yet.

has anyone made this work in parallel with Navilink? there’s a hint in post 80, albeit I haven’t bought this specific splitter/breakout.

[NyxVale63]

I got data flowing in from a Navien NHB series boiler. It seems the packet format is somewhat different, for example index #1 is 04 instead of 05 that seems to be the case in other equipment what I’ve seen here. The boiler has separate set points for Domestic Hot Water and Space Heating so the data seems to be in different locations. When I have some more time I will try to map it and share in case useful for anyone else.

[smurf12345 (Patrick)]

My memory is already failing me, but I want to say the 24v was on the small 2 pin connector just below the connector we are using for data.

[dacarson (David Carson)]

@smurf12345 Thanks, I’ll take a look at that connector.

With respect to command packets, I see pretty much the same pattern as @ejarrett documented earlier with a NaviLink attached.

I have not been able to work out what the byte after recirc. on/off does (byte 12). The ‘ack’ always follows the recirc. as documented, and byte 12 has the same value as the command. But subsequent commands have different values there.

I also see a value appear there for the On/Off command. For example, this is what I saw when I recently turned the unit off then on:

F7 05 0F 50 10 0C 4F 00 0B 00 00 00 AC 00 00 00 00 00 0C 
F7 05 0F 50 10 0C 4F 00 0A 00 00 00 26 00 00 00 00 00 E4 

Built a dashboard so I can observe the behavior of the unit. some of the visualizations are to help me understand the value.

[kamakazie2]

Hi all, just found this thread after having my Navien NPE240A2 installed.

I have an esp32/ wroom32 and a ttl to rs485 board wired up on a bread board.

I has python and esphome installed on my pc but ive mostly installed esp32 via web installs like wled and rat-gdo

I got to the point where i downloaded the files, out them on my hdd and run the esphome compile commands but i get an error that i didnt set the ota parameters.

Id love to get up and running and help out where i can.

Edit: Got it… had to run as administrator and i got it installed…

[ejarrett]

@dacarson

I have a 240A Navien unit. Like @smurf12345, I don’t see +12v power on Pin 1, and I am powering my ESP32 externally. I have a navilink unit, though it is not the stand alone unit, it is the unit that has a separate power supply and multiple ports. I would love to power it from the hot water unit, as I found this RS-485 HAT that is all-in-one for my Wemos boards.
@smurf12345 were you able to find the 12v pins?

I made a custom cable with an ethernet cable, and a JST connector (basically the same thing the original navilink connector is) then I spliced a Y into the other end, so I can have both the navilink and my esp32 listening to the same data.
My ESP runs off the water heater, but the navilink still has a power brick.
this is how the 12v works with the RS-485:
https://community.home-assistant.io/t/navien-esp32-navilink-interface/720567/39

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I have not seen those Off & On commands with byte 12, unless those are the received after an on/off command is sent.

[kamakazie2]

I was able to connect and receive data. This is great. I appreciate all of your efforts.

I did switch the Wroom 32 to use TX2 and RX2 in the yml file.

[kamakazie2]

I noticed that after a few hours i was getting everything set back to 32* with no updates. After looking at the setup i noticed the TTL board RX light was very faint. Almost as if the 3.3v was being exhausted. I saw on my amazon rs485 to TTL board it handles 3to 30v so i switched from the 3.3v pin to the vin pin which is getting 5v. And its been a few hours now without any issue. Have any of you experienced this who are using the ESP32 and TTL board combo?

[dacarson (David Carson)]

I always see numbers for byte 12 with the on/off command. Can I ask more about your configuration?
I have a NPE-240A with the NaviLink (not NaviLink Lite) unit attached, model BCM-CV10. I am not sure if it matters, but it the NPE is connected to COM port 1 on the NaviLink unit. I also don’t have the HotButton expansion board installed in the NPE.
I have this breakout board but I don’t see 12v on far left and far right pins. I am using the cable that came with the NaviLink unit to the breakout box.

[tabrisnet]

So I figured out part of it at least…
https://jheyman.github.io/blog/pages/RS485Sniffer/
said to connect RE & DE both to a GND on my ESP. I had previously left them floating. It now no longer breaks the NaviLink. But I’m not receiving any data on the UART.

Now i just have to find out how to decode the data from an NFB [which as noted by @NyxVale63] is probably very similar to the NHB.
Definitely looking forward to his update with the map of which bytes are which fields.

[htumanyan (Hovhannes Tumanyan)]

I have the same unit and believe the 240A does not provide the 12V on the rs485 connector. There is a “Wifi Upgrade” kit out there that replaces the front panel and that I suspected might be the part needed to get the 12V. However, when I called Navien asking about it (was asking if there is a way to feed NaviLink from the heater rather than 12V external brick) they surprised me by saying that NaviLink is not even compatible with 240A.

Side note - the connector next to RS485 does seem to have 5V on some pins. Still exploring to see what that connector is and if it is possible to power feed the ESP from that connector.

[tabrisnet]

fwiw, I’m powering my NaviLink from a PoE to 12V adapter. This lets me reboot it remotely, if necessary.

[strato]

I’m trying to piece together the breadcrumbs in this thread to get this going but it’s fragmented and difficult to follow. Is there any single source, git, or tutorial for this set up?

The esphome part looks mostly covered here: GitHub - evanjarrett/ESPHome-Navien: ESPHome configuration for RS-485 control of Navien Hot Water Heaters

But I’m struggling with the hardware resources.

[ejarrett]

I see the discrepancy, I have the 240A2 model which must have the 12v to support the navilink lite.

[ejarrett]

I opted for m5 stack posted here:

Navien, ESP32 Navilink interface

[photo_2024-05-14_12-22-13] here is a picture of my install. Using Atomic RS485 base and atom lite controller. XHB pigtails from aliexpress

and here:

Navien, ESP32 Navilink interface

@brystmar - Thank you for the offer! I just realized that my favorite connectors for my own projects are JST-XH and that they fit nicely into the XHB socket even though they don’t have a retainer clip. I did order a set of 20 5P XHB connectors, also on their way across the Pacific, but I can make a cable today using the XH connectors and just secure it to the cable next to it for the time being. This way, I can try to contribute more meaningfully to the project right away In revi…

The Atomic RS485, with the AtomS3, the post above links to the Atom Lite which will also work, I just standardize on the S3 version.
and bought a pack of JST connectors to make it fit in the unit, and used spare ethernet cable to wire it up (just because thats how the navilink cable is)

IMO this is the cleanest solution, but its more expensive than a cheap esp32 and rs485 adapter.

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The software side of things is a bit all over the place right now.
Everyone is still trying to figure out bits and pieces of everything. My yaml isn’t perfect, but it should provide a place to get started (theres other yaml copies in this thread as well),
while I think we could go the CPP route with @htumanyan’s implementation, I just don’t know if that’s the easiest for people to one-click install right now.

I might have more time in a few weeks to consolidate everything we know, unless someone else wants to get to it first.
Might be nice to make some github issues for the different bytes so that people can update with what they think is going on.

[dacarson (David Carson)]

@dacarson

I’ve investigating:
id(uart_water_byte8).publish_state(bytes[8]); // 0, 8, 32 related to recirc running
What I have seen is that when water is flowing but it is not heating, it has a value of 3. With the water still flowing and heating turns on (ie current gas > 0), it goes back to 0.

Correction to this. After graphing and examining the data and observing my usage, I have a better understanding of this byte. I have only seen 0 or 3 for water byte 8. When it is 3, hot water is flowing out of a tap somewhere, ie hot water is in use.
This is different to byte 18 water flow, in that if recirculation is running (I have external recirculation enabled) but no hot water is being used, it shows a value as water is technically flowing, just in a circle.