idm-heatpump-api 0.9.1

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 (Navigator 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
• Register-map invariants: docs/Register-Map-Invariants.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, heat-sink sensors, power limitation, and more.
• Safe Batch Reads: Grouping of exactly adjacent, non-overlapping register ranges (up to 40 registers per request) with automatic single-register fallback for implausible grouped values.
• Resilient: Configurable retries with adaptive exponential backoff, permanent-failure tracking for unavailable registers, and connection-suspect detection that forces a reconnect on dead sessions.
• Write Support: Safe register writes with datatype, enum, min/max and finiteness validation, EEPROM throttling, and cyclic-write heartbeats. Includes a dry_run/simulate_write path for validating without sending.
• Optional Web Supplement: Read-only access to local-web-only values (flow rate, hot gas, refrigerant pressure, board temperature, software version, …) via Navigator 10 WebSocket or Navigator 2.0 HTTP, including notifications and statistics.
• Metadata-Rich: Each register carries Home Assistant mapping fields plus source, source version, supported models, sentinel values, and verification metadata.
• Typed: Ships a py.typed marker and full inline type annotations.

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 default, 8 configurable)	Maintainer-confirmed
IDM Navigator 2.0	firmware-dependent	up to 7 (A–G)	firmware-dependent	Expected; needs broader raw detection captures
IDM Navigator Pro	firmware-dependent	up to 7 (A–G)	up to 10 (8 configurable)	Expected; needs complete diagnostics

Navigator 1.0/1.7 is a separate protocol family and is not supported.

Requirements

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

Installation

pip install idm-heatpump-api

For the optional local-web supplement (Navigator 10 WebSocket / Navigator 2.0 HTTP):

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

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.read_value("outdoor_temp") / client.set_value("dhw_setpoint", 48): Key-based read/write helpers (resolve via the registry).
• client.set_value("dhw_setpoint", 48, dry_run=True): Validate and encode a write without sending it. Returns a WriteSafetyResult.
• client.simulate_write(reg, value, dry_run=True): Lower-level validation/encoding of a RegisterDef or key; also returns WriteSafetyResult.
• client.write_register(custom_reg, value, allow_custom_register=True): Explicit advanced escape hatch for user-authorized raw writes. Model-map membership is skipped, but datatype and value-safety validation remains active.
• client.probe_register(address=1850, count=2): Probe a single register without affecting failure tracking.
• client.force_reconnect(): Hard-close the current TCP connection and open a fresh one.
• client.get_diagnostics(): Return an IdmClientDiagnostics snapshot (navigator type, connection state, firmware, last error, permanently-failed and batch-unsafe registers, connection-suspect flag).
• client.get_last_error_context() / client.clear_last_error_context(): Inspect the last structured ModbusErrorContext (operation, address, count, register type, error type, message, attempt).
• 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"). Useful for consumers that maintain their own polling skip-list; it never includes registers that merely failed repeatedly for a transient reason.
• client.get_batch_unsafe_registers() / client.mark_batch_unsafe(reg): Registers that produced an invalid grouped value are read individually for the rest of the client session. mark_batch_unsafe lets a consumer quarantine a register when an external plausibility check detects a valid-looking but incorrect grouped value.
• client.get_active_cyclic_writes() / client.get_expired_cyclic_writes() / client.reset_cyclic_write_state(): Track cyclic GLT write heartbeats. Successful writes to cyclic GLT registers refresh an in-memory deadline; consumers can detect stale external demands and clear the state on reload or shutdown.
• client.decode_value(registers, reg) / client.encode_value(value, reg): Public codec helpers (ModbusCodec mixin) for manual (de)serialization.

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

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.

See docs/Navigator-Protocol-Analysis.md for the validated local transport boundary, reverse-engineering evidence and explicitly unsupported protocol areas.

Two transports are supported:

• Navigator 10 — local WebSocket on port 61220 via IdmNavigator10WebClient (created through create_optional_navigator10_web_client()). Supports read_data(), read_statistics(), and read_notifications().
• Navigator 2.0 — local HTTP with CSRF token handling via IdmNavigator20WebClient (created through create_optional_navigator20_web_client()). Supports read_data(), read_extra_data(), and capabilities().

If the user does not configure a local network PIN, consumers should not create a web client. Both factories return None for None, empty, or whitespace-only PIN values so Modbus-only operation can continue without errors. Use web_pin_configured(pin) to check explicitly.

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.get_numeric("flowmeter"))

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

asyncio.run(main())

Web errors are raised as subclasses of IdmWebError (e.g. IdmWebConnectionError, IdmWebAuthenticationError/IdmWebPinRejectedError, IdmWebCsrfError, IdmWebProtocolError/IdmWebWebSocketError/IdmWebResponseError, IdmWebTimeoutError, IdmWebDependencyError). Short legacy aliases (AuthenticationError, ConnectionError, TimeoutError, CsrfError, WebSocketError, ProtocolError, PinRejectedError) remain available but the IdmWeb* names are preferred. The recommended web scan interval is RECOMMENDED_WEB_SCAN_INTERVAL (30 s).

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, protected by a snapshot test (tests/test_public_api.py). It currently includes:

• Client and metadata types: IdmModbusClient, IdmModelInfo, RegisterDef, DataType, RegisterType, WriteClass, WriteSafetyResult, ModbusErrorContext, ModbusCodec, IdmClientDiagnostics, FeatureFlags, IllegalAddressError, AdaptiveBackoff, PollRateLimiter, quiet_pymodbus_logging
• Register builders and registry: build_register_map, get_all_registers, get_register, get_register_registry, get_detection_registers, get_heating_circuit_registers, get_zone_module_registers, RegisterRegistry, CORE_REGISTERS
• Optional web supplement: IdmNavigator10WebClient, IdmNavigator20WebClient, create_optional_navigator10_web_client, create_optional_navigator20_web_client, web_pin_configured, IdmWebData, IdmWebValue, IdmWebValueDescription, IdmWebNotifications, IdmWebNotification, IdmWebDiagnostics, WEB_VALUE_DESCRIPTIONS, RECOMMENDED_WEB_SCAN_INTERVAL, IdmWebError, IdmWebDependencyError, IdmWebConnectionError, IdmWebTimeoutError, IdmWebAuthenticationError, IdmWebPinRejectedError, IdmWebCsrfError, IdmWebProtocolError, IdmWebWebSocketError, IdmWebResponseError, and the legacy aliases AuthenticationError, PinRejectedError, CsrfError, ConnectionError, TimeoutError, WebSocketError, ProtocolError
• Option maps: 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, MODEL_DETECTION_TIMEOUT, MODEL_DETECTION_MAX_RETRIES, 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

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
• Up to 8 configurable rooms per zone module (6 is the current Navigator 10 default)
• 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. See CONTRIBUTING.md and docs/Contributing (2).md for details.

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.