H-Link-Docs

This repository documents my implementation of Lumixen's excellent ESPHome custom component: lumixen/esphome-hlink-ac.

Note: AliExpress links may fluctuate in price and availability. These are not specific product endorsements.

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Hardware

Heat Pump

• Model Number: RAS-70YHA2

Components

• Connector JST PA2.0 (no modification):
  AliExpress Link

• Alternative connector JST PH2.0 (requires modification):
  AliExpress Link

• Logic Level Converter:
  AliExpress Link

• Buck Converter:
  AliExpress Link

• ESP32 (CP2102):
  AliExpress Link

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Instructions

Step 1: Heat Pump Disassembly

1. Power Off the Unit
   Turn off the heat pump at the main (master) switch. This is usually located near the outdoor unit. Ensure the green indicator light on the indoor unit is off.

2. Remove Three Screws
   These screws are located along the bottom edge of the indoor unit. Plastic covers must be removed to access them.

   

3. Release Six Clips
   Use a flathead screwdriver to release the four clips along the top, then two more under the filter cover.

   

4. Remove Electronics Housing Cover
   Remove any tape if present and unscrew the three screws securing the electronics housing.

5. Locate the H-Link Header

   

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Connector Modification

If using a PH2.0 connector, you will need to carefully file down both sides for it to fit.

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Determining Socket Orientation

Using a multimeter, identify the 12V and Ground pins. In my setup, the 12V pin was at the bottom:

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Wiring

Follow the reference wiring diagram. Use GPIO16 and GPIO17 for UART RX and TX respectively:

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ESPHome Configuration

esphome:
  name: hitachi-h-link-controller
  friendly_name: Hitachi AC

esp32:
  board: esp32dev
  framework:
    type: esp-idf

# Enable logging
logger:

# Enable Home Assistant API
api:
  encryption:
    key: "encryption key"

ota:
  - platform: esphome

wifi:
  ssid: Wifi
  password: WifiPassword

uart:
  id: hitachi_bus
  tx_pin: GPIO17
  rx_pin: GPIO16
  baud_rate: 9600
  parity: ODD

external_components:
  - source:
      type: git
      url: https://github.com/lumixen/esphome-hlink-ac.git
      ref: 2025.5.1
    components: [hlink_ac]

climate:
  - platform: hlink_ac
    name: "LoungeAC"
    hvac_actions: true  # Set to false if HVAC actions are not needed

switch:
  - platform: hlink_ac
    remote_lock:
      name: Remote Lock
    beeper:
      name: Beeper

sensor:
  - platform: hlink_ac
    outdoor_temperature:
      name: Outdoor Temperature

text_sensor:
  - platform: hlink_ac
    model_name:
      name: Model

number:
  - platform: hlink_ac
    auto_target_temperature_offset:
      name: Auto Mode Temperature Offset