[APP][Pro] Atlantic Cozytouch [EN]

[Nicolas_YDDER]

Control your Atlantic / Thermor / Sauter heating, hot water and air-conditioning devices from Homey Pro, through your Cozytouch bridge.

Install (test channel, v1.3.5): Atlantic Cozytouch | Homey
Source & issue tracker: GitHub - NicolasYDDER/homey-cozytouch · GitHub
User guide: homey-cozytouch/USERGUIDE.md at main · NicolasYDDER/homey-cozytouch · GitHub

The app is not published to the stable App Store yet — the test channel above is how you install it today. It is not affiliated with or endorsed by Groupe Atlantic: it talks to the Cozytouch cloud through a reverse-engineered API that can change without notice.

I have been posting releases in Atlantic Cozytouch App since March, but that topic started as a general app request back in 2023. This is now the dedicated thread — please post support questions, device reports and feedback here.

What you need

• Homey Pro, firmware 5.0 or later. The app runs locally on Homey Pro only — no Homey Cloud / Bridge support.
• A Cozytouch bridge already set up, with your devices working in the official Cozytouch mobile app.
• Your Cozytouch account email and password — the same ones you use in that app.

Setup, in short:

1. Install the app, then open Homey Settings → Apps → Atlantic Cozytouch.
2. Enter your Cozytouch email and password, hit Save credentials, then Test connection — it lists the devices found on each protocol.
3. Add devices the normal way: Devices → + → Atlantic Cozytouch → pick the device type. Credentials are reused, so you log in once, not once per device type.

How it works, and why some devices behave differently

Atlantic runs two separate clouds, and your gateway lives on one of them:

Backend	Typically	Auth
Cozytouch (Magellan), apis.groupe-atlantic.com	Newer boilers, towel racks, AC, recent tanks	OAuth2 password grant
Overkiz, ha110-1.overkiz.com	Older water heaters, io-homecontrol, Thermor / Sauter	Atlantic token → JWT → Overkiz login

The app logs in to both and merges the discovery, so you don’t have to know which one your bridge answers on. Each paired device remembers its protocol and commands are routed accordingly. Plenty of accounts only exist on one side — that is normal, not an error.

One global sync interval (default 60 s, range 30–300, in app settings) drives everything: each cycle asks Overkiz to refresh gateway states, then polls every paired device. Please keep it at 60–120 s — shorter risks an Overkiz QUOTA_EXCEEDED and devices dropping to unavailable.

Supported devices

Six device types: Radiator / Heating, Water Heater, Towel Rack, Heat Pump / AC, Pass Cozytouch, Shogun Zone Control.

Validated on real hardware

Device	Type	Protocol	What works
Atlantic Kelud (500 W)	Towel rack	Cozytouch	Mode, target + measured temperature, on/off
Sauter Asama	Towel dryer	Overkiz	Mode, target + measured temperature, on/off
Atlantic Calypso (thermodynamic tank)	Water heater	Overkiz	Mode, temperature, boost, away
Atlantic Pass Cozytouch (ref. 602251)	Wall module	Overkiz	Heating level, on/off
Shogun Zone Control	Main unit + zones	Overkiz	HVAC mode, per-zone temperature + mode, on/off, heat/cool tile colours
Sauter / Thermor Ipala	Radiator	Overkiz	Mode, target temperature, on/off

Mapped from user reports — should work, confirmations welcome

• Gas boilers and thermostats: Naema 2 Micro/Duo, Naia 2 Micro/Duo, Atlantic thermostats (Magellan models 56, 61, 65, 235, 418, 1444).
• Towel racks: Kelud, Kaoli, Asama (Magellan 1381, 1382, 1386, 1388, 1543, 1546, 1547, 1551, 1622, plus Overkiz AtlanticElectricalTowelDryer_IC3).
• Water heaters: Calypso including Calypso connecté 240 L (model 1658), Zeneo, Vizengo, Lineo, Égéo/MBL (Magellan 236, 389, 390, 1369–1376, 1642–1658, 1966, plus Overkiz CETHI_V4 and MBL).
• Heat pumps and AC: Loria Duo R32 standard and advanced, Takao M3 series.
• The Cozytouch bridge itself (models 556, 1353) is detected but intentionally not paired as a device.
• AC controller modules (models 562–570) are detected but not mapped yet.

Mode sets differ per protocol, because the two clouds do not expose the same modes: Overkiz tanks get Off / Manual / Eco / Auto, Magellan tanks get Off / Manual / Eco / Program.

Flows

Triggers: temperature changed, heating mode changed, Pass Cozytouch mode changed, Zone Control HVAC mode changed, boost turned on/off, away mode turned on/off.

Actions: set heating mode, set HVAC mode, set Zone Control HVAC mode, set Zone Control zone mode, set Pass Cozytouch mode, turn boost on/off, turn away mode on/off.

Conditions: heating mode is…, Zone Control HVAC mode is…, zone mode is…, boost is on, away mode is on.

Plus Homey’s built-in target-temperature and on/off cards. Everything you can do from a device tile is available in a Flow.

Known limitations — please read before reporting

Changes made on a wall remote can take a while to appear. Some Overkiz devices simply do not push state to the cloud until the gateway reports in. The app runs the cloud’s own refreshStates on every sync cycle, the same family of call the official apps make when you open them, but it cannot invent an update the gateway never sent. This is a documented Overkiz platform limitation, not Homey using a different backend. Quick check: open the Cozytouch app without changing anything — if it is stale too, the cloud is behind.

A device goes unavailable. Usually the sync interval is too short and you are being rate-limited. Raise it to 120 s.

Magellan answers per product, not per model. Two tanks in the same family can implement different capability IDs, so an unsupported device can look connected but empty. The app makes that visible instead of hiding it: it dumps the capability list once per app run, falls back to the setup view when the per-device endpoint returns nothing, puts a warning on the tile when nothing maps, and reports “This control does not exist on this device model” instead of raw API JSON.

Two things are known to be missing today: away mode on Magellan tanks (it is a setup-level property whose payload isn’t mapped yet) and full mapping for the AC controller modules.

Reporting a device that doesn’t work

This is how support for new products gets added, so the detail matters. Please include:

1. The commercial name and reference of the device, e.g. AQUEO ACI HYB VM 150 L 2200M.
2. Which device type you tried to pair it under, and what happened: not discovered, paired but empty, or a specific control fails.
3. The capability dump line from homey app log, or a Homey diagnostic report ID. On Magellan it looks like this:

Magellan capabilities (modelId 390, productId 7, capabilities endpoint): 1 "Mode"=0, 117=52.5, …

On Overkiz, the pairing error names the device with its controllableName, e.g. Chauffe-eau (io:AtlanticDomesticHotWaterProductionMBLComponent) — that string is what the mapping is keyed on. A pairing failure also lists every device that was found, in the app log.

Bug reports with logs are just as welcome on GitHub: Issues · NicolasYDDER/homey-cozytouch · GitHub

What’s new

1.4.8 — The room thermostat of an Alféa Excellia / Extensa heat pump read a mode indicator instead of its probe, so a room at 22 °C showed as 4 °C. Its setpoint, heating mode and on/off state now follow the appliance too.

1.4.7 — The settings page could show Overkiz as connected when the login had actually failed: the indicator only checked that a token had been obtained, not that the Overkiz login itself succeeded, so it disagreed with Test connection. Also recognizes the second channel of some two-zone towel dryers (modelId 1389), previously reported as an unknown type.

1.4.6 — Driver icons rendered as solid black shapes in the Homey mobile app. The phone’s SVG conversion does not inherit the root fill="none", so every outline now sets it explicitly.

Earlier in 1.4.x: heat pump support as described above, two more Magellan tanks mapped (AQUEO ACI HYB, Alféa Extensa Duo), product-accurate driver images, and fixes for devices reappearing at pairing and for “card unavailable” flashes in the Flow editor.

Full changelog: homey-cozytouch/CHANGELOG.md at main · NicolasYDDER/homey-cozytouch · GitHub

Credits

Big thanks to @cedric07, who contributed the Pass Cozytouch, Shogun Zone Control and Ipala support, the global sync work, and the driver images and icons. The protocol groundwork owes a lot to the cozytouch Home Assistant integration — reverse engineering this API twice would have been painful.

And thanks to everyone in the old thread who tested builds and sent logs from hardware I don’t own. That is the only way the device list grows.

Support the app, entirely optional and bug reports help more: PayPal

[smarthomesven]

Please fix the formatting.

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[Anthony_Cherpeau]

Hi Nicolas,

I have an Atlantic Alféa Extensa Duo A.I. 5 R32 (modelId 212) connected to Cozytouch and working correctly in the official Cozytouch app.

I am using your Atlantic Cozytouch app on a Homey Pro 2023, but my heat pump cannot be added.

During the discovery process, Homey detects my device and shows:

• Alféa Extensa Duo A.I. 5 R32
• modelId: 212
• AtlanticPassAPCHeatPumpMainComponent
• AtlanticPassAPCDHWComponent
• AtlanticPassAPCOutsideTemperatureSensor
• TotalElectricalEnergyConsumptionSensor

However, when I try to add the heat pump, Homey does not find any compatible device.

Homey: Homey Pro 2023
Heat pump: Atlantic Alféa Extensa Duo A.I. 5 R32
Model ID: 212
Cozytouch: working correctly with the official app

Here is my Homey diagnostic report ID:

6c817e3d-c371-42b2-91b3-661fef2bda58

Could you please check the diagnostic report and see whether this model/capability set can be mapped and added to the app?

I would be happy to test a new version if needed.

Thanks for your work!

[Nicolas_YDDER]

Hi @Anthony_Cherpeau ,

Diagnostic file received. Checking this point today to see how to had a compatibility with your heat pump.

[Nicolas_YDDER]

@Anthony_Cherpeau,

I tried to fix but some elements remain unclear, so next release need to be tested and reported.

Your heat pump was found but no driver claimed it. The Alféa Extensa Duo speaks Atlantic’s “Pass APC” protocol, and the app only supported that protocol for Shogun Zone Control systems, so all four components you saw on the discovery screen were skipped and pairing ended on “Aucun appareil compatible trouvé”. Nothing was wrong with your setup or your Cozytouch account.

The next release (1.4.0) adds a driver for this range. Pair it under the new type Pompe à chaleur (Alféa / Pass APC) and Homey will add:

• the main unit — mode (Arrêt / Chauffage), on/off, and the outside temperature from your heat pump’s outdoor probe;
• one device per heating circuit — for you that’s the “Plancher” circuit: setpoint, room temperature, and mode Arrêt / Manuel / Programme.

Your hot water tank is a separate device: run the pairing a second time and choose Chauffe-eau to add it (mode, setpoint, boost, absence).

Two things worth knowing:

• Your Extensa is heating-only, and the app now detects that from the heat pump itself, so it won’t offer you Cool / Dry / Auto modes it would refuse. Reversible models (Excellia) do get them.
• Command names differ from one Atlantic product to the next, so instead of guessing per model, the app now reads from your own heat pump which commands it accepts when you pair it. If some control turns out to be missing on your unit, it will say so explicitly rather than doing nothing, that message is exactly what I’d need to finish it.
• Your heat pump also appears on Atlantic’s other cloud (that’s the “modelId: 212” line). I deliberately did not add it there: it would give you a second tile for the same appliance that probably wouldn’t work. The four components you saw are the supported ones.

I don’t have this hardware, so please tell me how it behaves once you’ve updated; especially whether the setpoint on the “Plancher” circuit sticks and whether the outside temperature looks right. Ignore the earlier suggestion of pairing it under Radiateur / Chauffage; those drivers now deliberately skip heat pump endpoints because the commands there were the wrong ones.

Also, unrelated to your product but caused by your report: pairing failures now list every device found in the app log (yours ended in “+5”, which hid the component names), and the log line now includes each device’s internal component name.

[Olivier_Perrault]

Many thanks for everything you’re doing to be able to manage atlantic devices with our favourite app homey. Atlantic is a major supplier here in France, and your job is of major national importance ;-). I installed the 1.3.5 version and while testing the connection, my PAC (Atlantic Alféa Excellia M Duo) does not seem supported (seen as UNKNOWN). See below.

Can you confirm ? And if yes, when do you reckon that PAC will be supported ?

[Nicolas_YDDER]

Hi @Olivier_Perrault ,

Thanks for your message, I really appreciate it.

I’ve just released version 1.4.0, which adds support for the Alféa Extensa Duo.

Could you please test this new version and send me the diagnostic report?

I’ll then check whether any additional compatibility work is required and, if necessary, add support for your device.

Since I don’t have access to the hardware myself, I’m effectively developing blind. Your diagnostic report is therefore the only way I can identify and support new devices.

Thanks again for your help!

[Thilo]

Hi,

This is my diagnostic report for the Alféa Extens S Duo 8 from 2026

caf03f9c-8257-4688-bc15-213b9ec88246

Thank you for your effords, Thilo

[Olivier_Perrault]

many thanks for your swift answer. it says that no compatible device was found. Probably because the modelID is different. I checked my documentation, it says : Excellia M Duo 6 (526990)

[Thilo]

When trying to add the Alfea Heat pump I get this message:

[Nicolas_YDDER]

Hi @Thilo,

I release a quick fix to see if something is better.

@Olivier_Perrault can you also check this new release and open a new diag report if needed ?

New release: 1.4.1

[Thilo]

Hi Nicolas, thanks for your quick réaction.

Unfortunatly I get the same error when trying to add the Alféa

Regards Thilo

[Nicolas_YDDER]

The main heat pump unit (the “Alfea Extensa S” entries) is a separate, known limitation: right now this app only supports pairing that unit over the Overkiz protocol, but on your account it’s only being announced over Cozytouch/Magellan — that’s why it still shows as “no compatible device” even after the last update.

To fix this properly I need two things from you:

1. In the Cozytouch app settings inside Homey, is there an “Overkiz” login/connection test, and does it succeed for your account? (If Overkiz auth fails or returns nothing for this device, that points to a gateway/account-side issue rather than something I can fix in the app.)
2. If Overkiz genuinely doesn’t expose this unit for your setup, I’ll need the raw Magellan capability dump for modelId 2303 and 2327. You can get this by enabling debug logging (or pulling a diagnostic report) and searching the Homey app log for lines like Magellan capabilities (modelId 2303, productId ..., capabilities endpoint): ... right after pairing/discovery runs. Please send me that log line for both modelIds.

With that I can figure out whether this needs an Overkiz-side fix or a new Magellan capability mapping for the main unit, similar to what was done for your tank.

[Thilo]

Hi,

Overkiz was green ( connected) when I opened the app settings. It went red when I clicked test connection.

This is the Diagnostic report 05b215ad-8199-4aec-ac0f-101451e6710c

Merci !

[Nicolas_YDDER]

Hi @Thilo ,

I do a new test release 1.4.8 to fix the authentication issue.
Then we will see if the connectivity with Overkiz can now allow you heat pump to connect.

BR

[Thilo]

Hi Nicolas,
thanks for keeping on!
Unfortunatly there is no change. In the App Settings there are 7 devices found:

A+
Thilo

[Nicolas_YDDER]

Hi @Thilo ,

I did a 1.4.9 version to get a more detailed dump. So please send me diag report when you can.

BR

Nicolas.

[Thilo]

Hi Nicolas,
diagnostic report is 10fc8601-e386-4397-8a48-98320e2e0e60

A+

Thilo

[Nicolas_YDDER]

Good news first: your devices don’t need Overkiz.

The Overkiz 401 / No such user account in your log is expected for your account. Atlantic runs two separate clouds, and your Alféa Extensa S lives only on the Cozytouch one which connected fine and found all 7 of your devices. Nothing you type in the credentials field can change that, and nothing is broken because of it. You can ignore the red Overkiz line.

Why your two attempts failed: you used the driver called “Heat Pump (Alféa / Pass APC)”. That one only works with the Overkiz cloud, so on your account it correctly finds nothing, but the error message wrongly said your whole account had no compatible devices. Sorry, that’s our bug and it’s being fixed.

Five of your devices can be added right now. In Homey, add a device and pick these drivers instead:

Driver to choose	Adds
Water Heater	your hot water tank (DHW_0)
Heat Pump / AC	your two room thermostats (ROOM_0, ROOM_1)
Towel Rack	TESC_0 and TESC_1

Being upfront about what to expect, so nothing surprises you: the hot water tank should work properly. ROOM_0 should show your real room temperature — if it instead shows about 4 °C, please tell us, that’s a bug we thought we fixed. ROOM_1 quite likely will show about 4 °C. The two TESC devices will probably add but stay empty. Those last two are known gaps we’re working on — please report what you actually see either way.

The two devices named “Alfea Extensa S” (the heat pump unit itself) can’t be added yet by anyone. That’s what we need your help with:

Please send us this — it’s what unblocks your heat pump:

1. Go to Homey → Settings → Apps → Atlantic Cozytouch.
2. Press Test Connection.
3. Scroll down and open the section “Device details (for reporting an unsupported device)”.
4. Select all the text in that box and paste it in your reply.

It lists your device names and technical IDs, so have a quick look before posting publicly. That text contains exactly the information needed to add support for your Extensa S — without it we’re guessing.

[Thilo]

Hi,

All is exactly as you described it. I sent you the report via message
I have two circuits, one is swichted off Room_0 Shows the temperature of the enabeled circuit and Hot Water also shows the accurate temp
Towel racks show no value, error message „“currently not supported“ What are they good for?

Regards Thilo