idm-heatpump-api 0.7.0

Python library for communicating with IDM Navigator heat pumps via Modbus TCP. Used by the IDM Heatpump Home Assistant custom integration.

IDM Heatpump API

An asynchronous Python library for communicating with IDM Navigator heat pumps (2.0, Pro, and Navigator 10) over Modbus TCP.

This library is primarily designed to power the unofficial IDM Heatpump Home Assistant custom integration, but it can be used independently for any Python project that needs to monitor or control an IDM heat pump.

Documentation:

• GitHub Pages: https://xerolux.github.io/idm-heatpump-api/
• GitHub Wiki: https://github.com/Xerolux/idm-heatpump-api/wiki
• PyPI: https://pypi.org/project/idm-heatpump-api/
• API contract: docs/API-Contract.md

The docs/ directory is the single source of truth and is used for both GitHub Pages and Wiki sync.

Features

• Asynchronous: Fully async operations using pymodbus with automatic reconnection.
• Auto-Detection: Probes registers to detect the controller model, active heating circuits, zone modules, solar, ISC, PV, and cascade.
• Comprehensive Register Map: 100+ registers covering temperatures, energy, status, heating circuits (A-G), zone modules, solar, ISC, cascade, boosters, and more.
• Batch Reads: Intelligent grouping and batching of register reads for maximum efficiency.
• Resilient: Configurable retries with exponential backoff and permanent failure tracking for unavailable registers.
• Write Support: Safe register writes with validation, min/max bounds, and EEPROM-sensitive write protection.
• Metadata: Each register includes Home Assistant mapping fields plus source, source version, supported models, sentinel values, and verification metadata.

Supported Devices

Device	Firmware	Heating Circuits	Zone Modules	Status
IDM Navigator 10	NAV10_20.23+ (2025)	up to 7 (A-G)	up to 10 (6 rooms each)	Confirmed
IDM Navigator 2.0	all versions	up to 7 (A-G)	no	Confirmed
IDM Navigator Pro	all versions	up to 7 (A-G)	up to 10 (6 rooms each)	Confirmed

Requirements

• Modbus TCP must be enabled on the IDM controller (Settings -> Building Management -> Modbus TCP = On).
• Default port: 502
• Default slave ID: 1
• Python 3.12+

Installation

pip install idm-heatpump-api

Basic Usage

import asyncio
from idm_heatpump import IdmModbusClient, build_register_map

async def main():
    client = IdmModbusClient(host="192.168.1.100", port=502, slave_id=1)

    try:
        await client.connect()

        # Auto-detect model and capabilities
        model_info = await client.detect_model()
        print(f"Detected: {model_info.model_name} (firmware {model_info.firmware_version})")
        print(f"Circuits: {model_info.active_heating_circuits}")
        print(f"Solar: {model_info.has_solar}, ISC: {model_info.has_isc}")

        # Build register map based on detected model
        registers = build_register_map(model_info=model_info)

        # Read all registers in efficient batches
        values = await client.read_batch(list(registers.values()))

        for name, value in sorted(values.items()):
            reg = registers[name]
            unit = f" {reg.unit}" if reg.unit else ""
            print(f"  {name}: {value}{unit}")

        # Write a register (e.g. set DHW target temperature)
        if "dhw_setpoint" in registers:
            await client.write_register(registers["dhw_setpoint"], 48)

    finally:
        await client.disconnect()

if __name__ == "__main__":
    asyncio.run(main())

Advanced Usage

The library provides fine-grained control for advanced scenarios:

• build_register_map(circuits=["A", "B"], zone_modules=2, rooms_per_zone=4): Manual register map without auto-detection.
• get_heating_circuit_registers("A"): Registers for a single heating circuit.
• get_zone_module_registers(zone_index=1, room_count=6): Registers for a single zone module.
• client.probe_register(address=1850, count=2): Probe a single register without affecting failure tracking.
• client.reset_failed_registers(): Retry permanently failed registers.
• client.get_unsupported_registers(): Return the register names explicitly rejected by the controller with Modbus exception code 2 ("Illegal Data Address"). This is useful for consumers that maintain their own polling skip-list; it never includes registers that merely failed repeatedly for a transient reason.

Register metadata for HA integration mapping:

reg = registers["compressor_status_1"]
print(reg.binary)                # True -> BinarySensor
print(reg.writable)              # False
print(reg.write_only)            # False
print(reg.write_class)           # forbidden / volatile / cyclic / eeprom / write_only
print(reg.enabled_by_default)    # True
print(reg.state_class)           # None (or "measurement", "total_increasing")
print(reg.icon)                  # None (or "mdi:thermometer")
print(reg.exclude_from_write)    # None (or {255})
print(reg.source)                # official_idm_modbus
print(reg.source_version)        # source document / verification version
print(reg.supported_models)      # expected Navigator models
print(reg.sentinel_values)       # context-specific unavailable values
print(reg.last_verified)         # optional hardware verification label

Successful writes to cyclic GLT registers refresh an in-memory heartbeat deadline. Consumers can inspect get_active_cyclic_writes() and get_expired_cyclic_writes() to detect stale external demands and can clear the state with reset_cyclic_write_state() on reload or shutdown.

Optional Local Web Supplement

Some IDM values are available in the local web interface but not in the published Modbus map, for example flow rate, hot gas temperature, refrigerant pressure values, board temperature, central-unit battery voltage, and the controller software version. The optional idm_heatpump.web module is read-only and is intended to run alongside the Modbus client.

Install the optional dependency when using the web client:

pip install "idm-heatpump-api[web]"

Navigator 2.0 uses the local HTTP interface with CSRF token handling. Navigator 10 uses the local WebSocket interface on port 61220. A Home Assistant consumer should poll Modbus and web data in parallel, or start the web poll a few milliseconds after the Modbus poll if the controller needs gentler pacing:

import asyncio
from idm_heatpump import (
    IdmModbusClient,
    build_register_map,
    create_optional_navigator10_web_client,
)

async def main():
    modbus = IdmModbusClient("192.168.1.100")
    web = create_optional_navigator10_web_client("192.168.1.100", pin="1234")

    await modbus.connect()
    model_info = await modbus.detect_model()
    registers = build_register_map(model_info=model_info)

    if web is None:
        modbus_values = await modbus.read_batch(list(registers.values()))
        web_data = None
    else:
        modbus_task = modbus.read_batch(list(registers.values()))
        web_task = web.read_data()
        modbus_values, web_data = await asyncio.gather(modbus_task, web_task)

    if web_data is not None:
        print(web_data.navigator_version)
        print(web_data.software_version)
        print(web_data.heatpump_model)
        print(web_data.simple_values.get("flowmeter"))

    if web is not None:
        await web.close()
    await modbus.disconnect()

asyncio.run(main())

If the user does not configure a local network PIN, consumers should not create a web client. create_optional_navigator10_web_client() and create_optional_navigator20_web_client() return None for None, empty, or whitespace-only PIN values so Modbus-only operation can continue without errors.

Public API

Supported consumers should import from the package root:

from idm_heatpump import IdmModbusClient, build_register_map

The public API is the package root __all__ contract and is protected by a snapshot test. It currently includes:

• Client and metadata types: IdmModbusClient, IdmModelInfo, IllegalAddressError, ModbusErrorContext, RegisterDef, DataType, RegisterType, WriteClass, IdmWebData, IdmWebValue, IdmWebValueDescription
• Register builders: build_register_map, get_all_registers, get_register, get_detection_registers, get_heating_circuit_registers, get_zone_module_registers
• Optional web supplement helpers: create_optional_navigator10_web_client, create_optional_navigator20_web_client, web_pin_configured, WEB_VALUE_DESCRIPTIONS
• Register collections and option maps: CORE_REGISTERS, SYSTEM_MODE_OPTIONS, CIRCUIT_MODE_OPTIONS, ROOM_MODE_OPTIONS, ZONE_MODULE_MODE_OPTIONS, ACTIVE_HC_MODE_OPTIONS, SOLAR_MODE_OPTIONS, SMART_GRID_OPTIONS, ISC_MODE_OPTIONS, HP_OPERATING_MODE_OPTIONS, BIVALENCE_STATE_OPTIONS, BOOSTER_FAULT_OPTIONS, EVU_LOCK_OPTIONS, VARIABLE_INPUT_OPTIONS
• Model, feature, and connection constants: MODEL_NAVIGATOR_20, MODEL_NAVIGATOR_PRO, MODEL_NAVIGATOR_10, MODEL_UNKNOWN, FEATURE_HEATING_CIRCUITS, FEATURE_ZONE_MODULES, FEATURE_SOLAR, FEATURE_ISC, FEATURE_PV, FEATURE_CASCADE, HEATING_CIRCUIT_LETTERS, MAX_HEATING_CIRCUITS, MAX_ZONE_MODULES, MAX_ROOMS_PER_ZONE, DEFAULT_PORT, DEFAULT_SLAVE_ID, DEFAULT_TIMEOUT, MAX_RETRIES, RETRY_BACKOFF_BASE, EEPROM_SENSITIVE_ADDRESSES, RECOMMENDED_WEB_SCAN_INTERVAL

The package ships a py.typed marker so type checkers can consume its inline type annotations.

Imports from submodules such as idm_heatpump.client or idm_heatpump.registers are internal convenience imports and may change as the library is reorganized.

Navigator 10 Support

The library fully covers the official 2025 Navigator 10 Modbus TCP specification, including:

• Heat sink / plate heat exchanger sensors (flow rate in l/min at 1072)
• Power limitation registers (4108 / 4112) for demand response / peak shaving
• Complete Booster A + B (second heat generator) monitoring
• Additional source pump faults and external pump demand control
• Groundwater temperatures and more cascade bivalence points
• All zone module rooms (6 rooms per module on current hardware)
• PV / energy management, solar thermal, and ISC (Intelligent Surface Cooling)
• Cascade temperatures and bivalence points

Contributing

Please open an issue or pull request for bug reports, improvements, and documentation updates.

License

MIT License — see LICENSE.

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Support

This library is developed in my spare time. If you find it useful, consider supporting:

• Star the repository on GitHub
• Report bugs
• Share with other IDM heat pump owners

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Disclaimer

This project is an unofficial community project and is not affiliated with, endorsed by, or connected to IDM Energiesysteme GmbH.

All trademarks, logos, and product names (e.g., "IDM", "Navigator") are property of their respective owners. The logos and images used are solely for identifying the compatible device and are not used commercially.

This project is provided without any warranty. Use at your own risk — especially when writing Modbus registers.

IDM Energiesysteme GmbH has neither authorized nor endorsed this project.