Mill panel heater (generation 2)

esp8266 global Comes with ESPHome misc
Mill panel heater (generation 2) - desolder.jpg
Mill panel heater (generation 2) - removed.jpg
Mill panel heater (generation 2) - soldered.jpg

General Notes

Mill panel heaters are available in various versions. This component is specifically designed for Generation 2 panel heaters (not compatible with portable heater models). Have a look here to check which generation you have https://millheat.zendesk.com/hc/en-us/articles/360000252071-Which-generation-do-I-have. If you have a Generation 3 panel heater (which comes with a built-in ESP32), check out this component: https://github.com/ssieb/esphome_components/tree/mill/components/mill_heater To use this component with a Generation 2 panel heater, you’ll need to replace the HF-LPT120A module with an ESP8266.

HF-LPT120A desoldered

Solder the ESP8266 in place. Refer to the GPIO Pinout section for detailed instructions

GPIO Pinout

PIN (mill board)ESP8266Description
+3.3VVCCPower input (3.3V)
GNDGNDGround
WTXTX (GPIO1)UART transmitter
WRXRX (GPIO3)UART receiver

Configuration

substitutions:
  devicename: "millzero_heater"  #Lower case name
  friendly_name: "Mill Zero heater"
esphome:
  name: "${devicename}"
external_components:
  source:
    type: git
    url: https://github.com/owangen/esphome
  components: [ mill_panelheater_gen2 ]
esp8266:
  board: d1_mini
wifi:
  ssid: !secret wifi_ssid
  password: !secret wifi_password
  ap:
captive_portal:
# Enable logging
logger:
  baud_rate: 0 # Deactived to prevent conflict with UART, sending UART to mill controller does not work if enabled
# Enable Home Assistant API
api:
ota:
uart:
  id: uart_bus
  tx_pin: GPIO01
  rx_pin: GPIO03
  baud_rate: 9600
climate:
  - platform: mill_panelheater_gen2
    name: Mill heater

Credits

This component is based on the work by https://github.com/JDolven/Replacing-HF_LPT120A-in-a-millheat-heater and https://github.com/trondsundt/MillHeat-ESPHome-NodeMCU