No response to Connect Request - HRVU LGH-50RVX-E.

[L4ky]

Hello, i'm playing a bit with the Mitsubishi installation in our business unit.
I successfully connected the D1 Mini using esphome and the esphome-mitsubishiheatpump library.

Now i'm trying to connect to our Heat Recovery Ventilation Unit without success. The model is LGH-50RVX-E.

Using MitsubishiCN105ESPHome i see that there is absolutely 0 response to the CONNECT REQUEST sent by the D1Mini ( [12:32:05][D][WRITE:157]: FC 5A 01 30 02 CA 01 A8 )

I tried many baud rates ( 2400 4900 9600 19200 and 115200 ). Always 0 response.

Any hint?

[echavet]

Well, hard to tell!

1st. You could try the chip from the working first setup on the unit that doesn't work
2nd. You could try to add a voltage regulator
3rd. You could try with a more reliable chip, like an esp32 S3
And at the end you could consider that maybe the unit is not supported

[L4ky]

And at the end you could consider that maybe the unit is not supported

I actually reached this conclusion, but i was hoping some hints on how to approach to support it.

Pre-installed control unit allows to change between 2 working modes + Auto mode, it also allow to regulate fan speed.

[echavet]

hey @L4ky
can I close this issue?
I think nobody can help because this is a specific unit.

[dwmw2]

What do you get if you send it these bytes at 2400 or 9600 baud:

02 FF FF 00 00 00 00 02

[L4ky]

What do you get if you send it these bytes at 2400 or 9600 baud:

02 FF FF 00 00 00 00 02

Absolutely nothing.
I already tried with:

  - platform: uart
    name: "Connect Request 1"
    data: [0x02, 0xff, 0xff, 0x00, 0x00, 0x00, 0x00, 0x02]
  - platform: uart
    name: "Connect Request 2"
    data: [0x02, 0xff, 0xff, 0x01, 0x00, 0x00, 0x01, 0x00, 0x00]
  - platform: uart
    name: "Connect Request 3"
    data: [0xfc, 0x5a, 0x02, 0x7a, 0x02, 0xca, 0x01, 0x5d]
  - platform: uart
    name: "Connect Request 4"
    data: [0xfc, 0x5b, 0x02, 0x7a, 0x01, 0xc9, 0x5f]
  - platform: uart
    name: "Connect Request 5"
    data: [0xfc, 0x41, 0x02, 0x7a, 0x10, 0x34, 0x00, 0x01, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0xfd]

[dwmw2]

But you have a pre-installed control unit on this port which does work?

[dwmw2]

Using an ESP32 box with two serial ports (e.g.https://www.tindie.com/products/thehognl/heishamon-communication-pcb/ ) I couldn't get uart_mitm to work, but I did manage to get it to relay packets back and forth as pure waveforms using the remote_receiver and remote_transmitter components:

remote_receiver:
 - id: proxy_rx
   pin:
     number: GPIO9
     inverted: true
   dump: raw
   rmt_channel: 4
   clock_divider: 40
   filter: 5us
   idle: 100ms
   on_raw:
     then:
       - if:
          condition:
            mqtt.connected:
          then:
           - remote_transmitter.transmit_raw:
              transmitter_id: ecodan_tx
              code: !lambda return x;
 - id: ecodan_rx
   pin:
     number: GPIO18
     inverted: true
   dump: raw
   rmt_channel: 5
   clock_divider: 40
   filter: 5us
   idle: 100ms
   on_raw:
     then:
       - remote_transmitter.transmit_raw:
          transmitter_id: proxy_tx
          code: !lambda return x;

remote_transmitter:
 - id: proxy_tx
   pin:
    number: GPIO8
    inverted: true
   rmt_channel: 1
   carrier_duty_percent: 100
 - id: ecodan_tx
   pin:
     number: GPIO17
     inverted: true
   rmt_channel: 3
   carrier_duty_percent: 100

We can then look at the logged packets using https://dbuezas.github.io/esphome-remote_receiver-oscilloscope/

[L4ky]

But you have a pre-installed control unit on this port which does work?

I'm not sure if it works.
I already tried multiple ESP without success.

Same setup on the HVAC works fine.

I was thinking about using the manual control ports which lets you set fan speed and mode by closing the circuit on different contacts.