Atlantic AGILIA IO electric radiator

An electric radiator with a built-in display, sold by Atlantic mainly in France. It speaks io-homecontrol two-way, so the hub sets its temperature and mode and reads back the room temperature and whether it is heating. Three radiators are confirmed on a Heltec V3 (SX1262) with the climate: platform; see Heating and climate for every option.

What works

Capability	Status
Discover & Pair	✅ Confirmed on three radiators; the hub pulls each radiator's own key
Target temperature	✅ Confirmed — the display follows, and the hub reads the value back
Off, Heat, Auto and the Program preset	✅ Confirmed — the display follows, and the hub reads the mode back
Room temperature	✅ Confirmed
Heating / idle	✅ Confirmed; follows a change from Home Assistant at the poll 45 seconds later, other changes at the regular poll (every 5 minutes by default)
Maximum setpoint	✅ Confirmed — the radiator reports 28.0 °C
Window sensor	✅ Confirmed — turns on when a window near the radiator is opened
Open Window Detection switch	⚠️ Reads back the radiator's setting; switching detection off from Home Assistant is not tested yet

Modes in Home Assistant

The radiator has three operating modes, described in its installation manual. Home Assistant has no separate mode for the two automatic modes, so both appear as auto, with a preset that tells them apart:

Radiator display	Home Assistant
BASIC — holds the set temperature, smart functions off	heat
AUTO — learns when the room is used and adjusts the temperature	auto with the Auto preset
PROG — follows the radiator's weekly program	auto with the Program preset
Off	off

Choose Program or Auto to switch between the radiator's automatic modes; heat or off leaves them. The weekly program itself is edited on the radiator. The radiator shares its node type with the Atlantic Adelis towel dryer, which shows the comfort or eco period of its program, so that period may be visible here too. If you run the radiator in PROG, please open an issue so we can check it.

How a radiator appears on the radio

Each radiator answers as two io-homecontrol nodes:

• The pairing node answers Discover & Pair. It presents itself as a remote controller (node type 1023), refuses a key from the hub, and hands over its own key instead.
• The heater is an electrical heater with an adjustable setpoint (node type 52, subtype 1), and it is the node your climate: entry controls. On a radiator as delivered it sits at the next address up (pairing node + 1).

Each radiator has a key of its own. The hub handles both points for you: Discover & Pair pulls the key, reads the heater at the next address under that key, and prints a block for the heater with that key in it. If the heater does not answer that read, the hub looks for it with a roll-call instead, which takes about 20 seconds.

Resetting a radiator's connections

The radiator's Expert menu (hold both arrow keys for more than 3 seconds) can delete all its connections. That gives the radiator a new key and new addresses for both nodes, and the new heater address is unrelated to the new pairing address. Your existing climate: entry for it stops working: pair the radiator again and replace the entry with the new block. The hub finds the heater with its roll-call, so this pairing takes about 20 seconds.

Pairing a radiator

Pair one radiator at a time. The menus are in French.

1. On the radiator, press the round button to open the menu.
2. Scroll down to Paramètres and press the round button.
3. Choose Connectivité and press the round button.
4. Choose Connexion and press the round button. The radiator shows an hourglass while it waits.
5. In Home Assistant, press Discover & Pair on the hub.

The pairing takes a few seconds, or about 15 seconds when the hub has to fall back to a roll-call to find the heater. The radiator then reports that the device was added ("Appareil ajouté avec succès"). The hub's log prints a report between DEVICE KEY RECEIVED -- DO NOT SHARE IT and END OF DEVICE KEY REPORT, with a climate: block for the heater that includes the radiator's system_key:.

1. Put the key into secrets.yaml, not into your main YAML.
2. Paste the block under climate:, replace the key with !secret ..., and give it a name.
3. Flash the hub.

Until you flash, the hub controls the heater with the pulled key; after a reboot it needs the system_key: in your YAML.

When no block is printed

If neither the direct read nor the roll-call reaches the heater, the log says outcome=key_received and prints the key without a block for the heater. Run Discover & Pair again with the radiator in Connexion mode, or put the key into a climate: entry's system_key:, flash, and press Scan Paired Devices. The heater answers only some roll-call requests, so repeat the scan if it finds nothing.

A radiator that already holds the hub's own key (for example, one you paired before by setting its key as the hub's system_key:) gets a block without system_key:, because its heater uses the hub's key. If the hub cannot reach the heater, the attempt ends as hub_key_returned: press Scan Paired Devices, and again if nothing answers.

Pairing the same radiator again before you flash prints its block again. Press Discover & Pair once per attempt: a press made while an attempt runs is ignored, with a log line saying so.

Working YAML

climate:
  - platform: home_io_control
    name: "Bedroom radiator"
    io_device_id: "986111"
    io_device_type: "electrical_heater"
    io_subtype: 1
    system_key: !secret bedroom_radiator_key

io_device_id is the heater's address as the printed block shows it. Give every radiator its own entry with its own system_key:.

Sauter Hekla

The Sauter Hekla, an electric heater from the same group, pairs and works the same way. It is confirmed on three heaters that were already paired with a Sauter Cozytouch, on a Heltec V3 (issue #222). The differences:

• The pairing menu is in the expert menu: Menu expert → Paramétrages → Connectivité → Envoyer clé. Choose it on the heater, then press Discover & Pair on the hub.
• One key for all heaters on a Cozytouch. A heater paired with a Cozytouch holds the key of the Cozytouch installation, so every heater on it hands over the same key. Pair one heater; for the others you need only their address, which you can take from the hub's log while the Cozytouch talks to them, and the same system_key:.
• The Cozytouch keeps working. Pairing with the hub reads the heater's key and leaves it unchanged, so the heater stays controllable from the Cozytouch app. A change made in the app shows in Home Assistant at the next poll: the hub polls each heater every status_poll_interval, and shortly after it hears the Cozytouch talk to a heater.
• The night light gets a light entity with io_model: heater_with_light and a night_light: block; see Heaters with a night light. Reading it is confirmed; switching and dimming it from Home Assistant are experimental.

climate:
  - platform: home_io_control
    name: "Kids' room heater"
    io_device_id: "29FB38"
    io_device_type: "electrical_heater"
    io_subtype: 1
    io_model: heater_with_light
    system_key: !secret cozytouch_key
    night_light:
      name: "Kids' room night light"

Known quirks

• Heating / idle trails the radiator. The hub reads the regulator when it polls: 45 seconds after a change from Home Assistant, and every status_poll_interval otherwise. A change made at the radiator, or a failed poll, can leave the card behind until the next poll.
• A radiator far from the hub misses some replies. A radiator received at about -60 dBm lost several replies to the hub's challenge answer, so its Unconfirmed Exchanges counter rose and a setpoint change sometimes had to be repeated. A radiator at about -40 dBm had no such failures.
• The pairing can lose the radiator's proof of its key. The hub challenges up to three times. If no answer comes back, the log says not proven: no 0x3D received and the hub looks for the heater under that key instead: a heater that answers proves the key, and the pairing completes. If nothing answers, the key is not printed; press Discover & Pair again. The radiator hands over the same key every time.
• The device name is generic. The heater reports its name as I2G_Actuator.

Evidence

Six corpus captures from issue #165, on a Heltec V3 with the SX1262 driver:

• A full pairing with the key pull and the roll-call that finds the heater
• A pairing of a radiator that already holds the hub's key, where the roll-call stays silent
• A Scan Paired Devices where the heater answers once, a second after the request
• The climate entity's read-back of seven registers
• A setpoint change and Off, each read back
• Heat, Auto and Program, each read back

An earlier capture shows the radiator refusing a pushed key: atlantic_agilia_pairing_key_transfer_command_unknown.

See also

• Heating and climate
• Pairing
• Supported devices