ecodan-ha-local

ESP32 compatible program for local monitoring of Mitsubishi Ecodan Air to Water heat pumps with automatic discovery in HomeAssistant.

Uses the CN105 connector on the Cased Flow Temp Controller (FTC6 in my setup) to do very basic control (zone 1 temperature set point, DHW temperature set point, boost DHW) + retrieve basic sensor information from the heat pump.

Hardware Dependencies

• ESP32-compatible development board (I'm using a LOLIN S2 Mini)
  • Will almost certainly exceed the memory budgets on an ESP8266, as I've not been super careful about memory usage.
• CN105 female connector + pigtails, as described here.
  • Note: The software is configured to use Serial UART1 on the ESP32, explicitly labelled TX/RX pins on a pinout will usually be pre-assigned to UART0.

Library Dependencies

• ArduinoJson v6.21.2
• Seeed_Arduino_mbedtls v3.0.1
• MQTT v2.5.1

First Time Setup

• Clone this repository and build with the Arduino IDE
• Flash the image to the ESP32 board
• Take the board out of firmware update mode, and it should broadcast a wireless network called ecodan_ha_local, connect to this network
• Configure the device to match your setup (see Software Configuration)

Deploying Updates

After initial flashing + configuration is completed, it's possible to update the firmware over your WiFi network by:

• Building the firmware binary with: Sketch > Export Compiled Binary
• Visit the configuration page for your device, by default this will be: http://ecodan-ha-local/configuration
• Scroll down to the Firmware Update section at the bottom of the configuration page
• Select the firmware binary which should be inside a folder such as build\esp32.esp32.esp32s2\ecodan-ha-local.ino.bin under Sketch > Show Sketch Folder
• Hit the "Update" button, the firmware update should proceed, and load back to the home page when completed

Software Configuration

Device Password

Setting a device password will cause the web interface to require the password to be specified each time the board is booted, or the client's browser cookies are cleared.

It's strongly recommended to enable this setting in case the device falls back to broadcasting an open access point, as it will retain other configuration values (MQTT passwords, server, Wifi SSID/Password) which may then be readable by anyone.

Default	Required
""	No

Serial Rx Port

The GPIO pin number which should be used for Serial data receive.

Default	Required
27	Yes

Serial Tx Port

The GPIO pin number which should be used for Serial data transmit.

Default	Required
26	Yes

Status LED Port

The GPIO pin number which should be used for the status LED. The following flashing patterns are possible:

• 2 short flashes, followed by one long flash: Serial connection to the Heat Pump has not been established.
• Steady long flashes: Network connection to the MQTT server has not been established
• Constantly lit: Status is OK

Default	Required
LED_BUILTIN	No

Dump Serial Packets

Dump packets sent to/received from the heat pump to the diagnostic log window on the Diagnostics page.

Default	Required
Off	No

WiFi SSID

The SSID of the WiFi network which you'd like the device to connect to. When the diagnostics page is loaded, the device will automatically initiate a scan for available WiFi networks and populate the menu when it completes.

Note: If this setting or "WiFi Password" are unset, the device will continue to boot into a captive portal access point.

Default	Required
""	Yes

WiFi Password

The passphrase/password which should be used when connecting to the previously specified WiFi SSID.

Note: If this setting or "WiFi SSID" are unset, the device will continue to boot into a captive portal access point.

Default	Required
""	Yes

Hostname

The network hostname the device will use to identify itself.

Default	Required
ecodan_ha_local	No

MQTT Server

The IP address or hostname of the MQTT server on your local network.

Default	Required
""	No

MQTT Port

The port on which your MQTT server is listening.

Default	Required
1883	No

MQTT User

The username which should be used when connecting to the specified MQTT Server.

Default	Required
""	No

MQTT Password

The password for the given MQTT User.

Default	Required
""	No

MQTT Topic

The topic value which the server should use to filter messages related to this heat pump.

Default	Required
ecodan_hp	Yes

See Also

There are a number of existing solutions for connecting to Mitsubish heat pump models via the CN105 connector, I wouldn't have been able to put this together without work already done here:

• https://github.com/m000c400/Mitsubishi-CN105-Protocol-Decode
• https://github.com/BartGijsbers/CN105Gateway
• https://github.com/gysmo38/mitsubishi2MQTT