Lennox iComfort DDS Bridge

Home Assistant support for Lennox iComfort thermostats that have been migrated to the Lennox "prod4"/v4 cloud (notably the iComfort M30), which the classic lennoxs30 / lennoxs30api message-bus path can no longer reach.

• ✅ Live climate + temperature/humidity, local push
• ✅ Control: setpoints, HVAC mode, fan, and Away (true state, reflected back)
• ✅ Outdoor temperature + weather (humidity, wind), HVAC fault alerts, filter/maintenance reminders, and Smart Away — as HA sensors
• ✅ Read-only status flags (allergen defender, ventilation, aux heat, defrost, …) surfaced as binary sensors when your model reports them
• ✅ No manual certificates — the add-on provisions itself from your Lennox login

Why this exists

Lennox migrated some accounts to a new backend. On prod4 the mobile message bus only delivers to an applicationid Lennox has already registered — a self-generated client subscribes, gets Ok, and then retrieve returns {"messages":[]} forever (see lennoxs30api#101).

This project takes the other data plane the app uses: the thermostat's realtime state flows over OpenDDS (DDS-RTPS + DDS-Security) through Lennox's RtpsRelay, and a DDS participant authenticates with its own minted identity — so there's no app-id allowlist to get past.

How it works

HA ── WebSocket ──▶ DDS bridge (this add-on) ── DDS-RTPS/Security ──▶ Lennox RtpsRelay ──▶ M30
        ▲                                                                   
   lennox_dds integration (climate + sensors, control)                     

1. Log in (prod4 gateway) → registerLCCOwner → a plant token with DDS.LCC_OWNER.
2. Provision a DDS-Security bundle from plantdevices/v1/dds-im/ — CA + governance, a minted participant identity (newcert?nonce=), and permissions (/permissions/DDS.LCC_OWNER?nonce=, same nonce).
3. Join domain 0, partition = your homeId, over the RtpsRelay; subscribe the LCC Zone Status topic → live zoneStatus. Control = writes to the Owner Schedule Update topic (setpoints / mode / fan) and Owner Manual Away (manualAwayUpdate, the Away switch).

The bridge is a tiny C++ OpenDDS subscriber + a Python server that streams JSON to a local WebSocket; the companion lennox_dds HA integration (a thin local_push client, auto-wired by Supervisor discovery) turns that into entities.

Install

You need both halves: the add-on (the DDS bridge — requires Home Assistant OS / Supervised) and the integration (the entities — requires HACS). The buttons open the dialog on your Home Assistant.

1. Add-on    → install Lennox iComfort DDS Bridge, set lennox_email + lennox_password, and Start. It provisions the DDS-Security bundle and auto-derives your home_id. (Manual: Settings → Add-ons → Store → ⋮ → Repositories → add https://github.com/challgren/lennox-dds. Advanced/offline: leave the credentials blank and drop your own bundle — see lennox_dds/.)

2. Integration    → Download, then restart Home Assistant. (Manual: HACS → ⋮ → Custom repositories → add the same URL as category Integration.)

3. Done — the add-on announces itself and the integration auto-configures via Supervisor discovery; your climate + temperature/humidity entities appear (no host or port to type).

Entities

All are created automatically per system/zone; ones your model doesn't report simply don't appear.

Entity	Type	Source
Thermostat	climate	setpoints, HVAC mode, fan, current temp/humidity
Away	switch	true state from LCC Manual Away Status, writable
Temperature / Humidity	sensor	per-zone zoneStatus
Cool Setpoint / Heat Setpoint	sensor	active period csp/hsp — both shown in every mode, so setpoint changes land in history + the logbook
Humidify / Dehumidify Setpoint	number	husp/desp — settable %RH targets, created only when your system has humidity control
Outdoor Temperature	sensor	weather-service value (falls back to the outdoor-unit sensor)
Outdoor Humidity / Wind Speed	sensor	LCC Weather Status
Alert	binary_sensor (problem)	active faults from LCC Alert Active/Cleared (codes + messages)
Maintenance Due	binary_sensor (problem)	filter/maintenance reminders + % remaining
Smart Away	binary_sensor	geofence away enabled
Demand Response Event	binary_sensor	utility OpenADR/AHRI-1380 peak event (pending/opt-out/start/end)
Allergen Defender, Ventilation, Aux Heat, …	binary_sensor	zoneStatus flags, only when your model marks them valid

Control is also available over MQTT (mqtt_enabled) for external/non-HA use — see the add-on docs. Download diagnostics (⋮ on the device) for a full, redacted dump.

This one repo serves three things: the integration (custom_components/, via HACS), the add-on (lennox_dds/, via the Add-on Store), and the image build source (container/, via CI).

Repository layout

custom_components/lennox_dds/  # the HA integration (via HACS) — climate + sensors + numbers
lennox_dds/                    # the HA add-on (prebuilt-image manifest -> ghcr.io/challgren/lennox-dds)
container/                     # the Docker image build source (Dockerfiles, C++ subscriber,
                               #   IDL, XCDR2 interop patch, bridge server, credentialed fetch)
.github/                       # CI: build-image.yml (per-commit) + release.yml (v* tag -> release)

Each directory has its own README. The add-on pulls a prebuilt image (fast install, no on-server compile); CI builds and publishes it to GHCR. See container/ for the internals and the one interop note (the device runs an OCI-proprietary OpenDDS 3.22 pkg-21, so a from-source OpenDDS needs the skip_sequence_dheader XTypes patch).

Reporting a bug

Please open an issue and attach a diagnostics file — it's the fastest way to a fix:

1. Settings → Devices & Services → Lennox iComfort (DDS) → ⋮ → Download diagnostics. It's auto-redacted (no sysID, no credentials) and includes the integration version, decoded status flags, and an unrecognized_fields section that flags data your model exposes but the integration doesn't handle yet.
2. For control or data problems, set debug: true in the add-on config and restart — the add-on log then prints every raw sample ([raw] {…}). Paste the relevant lines into the issue.

Different hardware (S30/E30, PureAir, humidifiers, multi-zone) reports fields the base M30 doesn't; a diagnostics file from your device is how we add support.

Status / credits

Reverse-engineered from the Lennox Home app against a live M30; shared upstream at lennoxs30api#101. Not affiliated with Lennox. Use at your own risk.