HeishaMon Communication PCB

HeishaMon Communication PCB

The HeishaMon Communication PCB is an open-source interface board designed for local monitoring and control of Panasonic Aquarea heat pumps (H, J, K, L, and M series). It eliminates the need for cloud connectivity by providing direct MQTT and HTTP API access to heat pump data, making it ideal for Home Assistant and other smart home platforms.

How It Works

The board connects to the Panasonic heat pump's CN-CNT (indoor unit) or CN-NMODE (outdoor unit) connector using a standard serial UART interface at 9600 baud (8E1). A level shifter converts between the heat pump's 5V logic and the ESP's 3.3V levels. Once connected, the HeishaMon firmware reads all available heat pump parameters — temperatures, flow rates, operating modes, error codes, and energy consumption — and publishes them via MQTT topics.

Two Board Variants

• Small board (ESP8266, Wemos D1 mini form factor): The original compact design with WiFi connectivity, 1-Wire temperature sensor support, and two S0 pulse meter inputs for energy monitoring. Powered via USB-C or directly from the heat pump's 5V supply.
• Large board (ESP32-S3): An expanded version adding optional W5500 Ethernet connectivity, two onboard 230V/5A relays for controlling external heating elements or pumps, and additional GPIO for peripherals.

Key Features

• Full heat pump telemetry: Reads 200+ parameters from Panasonic Aquarea heat pumps including water temperatures, compressor frequency, COP, and error codes
• MQTT integration: Publishes all data to MQTT topics with configurable update intervals for seamless Home Assistant, Node-RED, or openHAB integration
• HTTP API and web dashboard: Built-in web interface for configuration, real-time monitoring, and firmware updates (OTA)
• 1-Wire temperature sensors: Connect up to 15 DS18B20 sensors on GPIO4 for monitoring additional temperatures (buffer tanks, room sensors, outdoor)
• S0 pulse energy metering: Two S0 inputs (GPIO12, GPIO14) for connecting kWh pulse meters to track energy consumption
• Optional Ethernet: W5500 SPI Ethernet module support on the large board for wired network reliability
• Optional relays: Two 230V/5A relays on the large board for switching external devices based on heat pump state

Community and Ecosystem

HeishaMon has a thriving community with thousands of active installations. Community contributions include:

• Home Assistant integration with auto-discovery
• Node-RED control flows for advanced automation
• ESPHome configuration for those preferring YAML-based setups
• Multiple 3D-printed enclosure designs on Thingiverse and Printables

Compatibility

Supported Panasonic Aquarea heat pump series:

• H-series (2012+)
• J-series (2014+)
• K-series (2018+)
• L-series (2021+)
• M-series (2023+)

Both monoblock and split system configurations are supported.