[APP][Pro] Komfovent C6M – local Modbus control, Energy & Dashboard

[Namlosen]

Komfovent C6M is an independent Community app for local control and monitoring of compatible Komfovent DOMEKT ventilation units from Homey Pro.

Update, 4 November 2026: v1.9.1 is available in Test (Build 19) and has been submitted for review. It adds active-target WHEN cards, on/off control and native holiday scheduling with an early-end card. The duplicate fan-slider page has been removed; saved profiles and all three Dashboard sizes are kept. Existing devices upgrade without re-pairing. Physical checks and the remaining beta tests are explained in the release update. This is not a Live release.

Install the Test version: Komfovent C6M | Homey

What is included

• One-tap modes: Away, Normal, Intensive and Boost
• Linked and separate targets for all four saved standard profiles: percentage control, plus experimental opt-in CAV control in confirmed m³/h or l/s
• Profile-specific electric reheating permission, separate from actual heater output
• Live fan levels, temperatures, filter life, alarms and unit status
• Panel 1/2 temperatures, display-panel selection and the active profile temperature target
• Flow action for saved standard-profile temperature targets, 5–40 °C in 0.1 °C steps
• WHEN cards for changes to active airflow and temperature targets
• Optional on/off Flow action
• Native holiday dates and an early-end Flow action, with a separate beta setting
• Native Homey Energy support with live power in W and total consumption in kWh
• Automatic Insights history and standard Energy Flow triggers
• Three Homey Dashboard sizes: Mini, Compact and Advanced; Mini includes a reheating-permission switch
• Flow actions and conditions for automation from other smart-home devices
• Fully local Modbus TCP communication; no vendor cloud account or analytics

Compatibility

The main local test unit is DOMEKT R700 with C6M firmware 1.4.47.74. Pairing performs a read-only compatibility check before adding the device. A Homey Pro and a correctly configured C6/C6M controller with Modbus TCP enabled and a reserved local IP address are required.

Earlier beta feedback also covers W1 handling and profile control on an R400 H, and CAV monitoring on an R450. Those reports are not a full qualification of every model or firmware. Validated CAV configurations can now be paired, but CAV control is a separate opt-in beta setting. Please check the physical response on your unit and report your model, firmware and units. VAV/DCV and unknown configurations are not supported for control.

R700 checks cover panel 1, active-target Flow triggers, on/off, Holiday microventilation, early cancellation and return at the unit’s day change. Tester feedback also confirms both panel-temperature display options. Other temperature profiles/control methods, physical CAV writes and multi-day Holiday cycles still need confirmation. The original R450 disconnection report has not been root-caused. Sensor availability depends on the unit and its connected hardware.

Control scope

Standard control covers the four documented modes, complete supply/extract pairs for their saved profiles, profile-specific reheating permission and the four standard profiles’ temperature targets. Optional on/off uses the unit’s own command; it is not a mains isolator. Holiday writes only its native date pair, not a special-mode command. On/off, temperature and Holiday control have separate settings, off by default. Changes use exact readback verification. Temperature targets do not change the control sensor or force heating on.

Holiday follows the unit’s own clock and existing microventilation/heating settings. Check the dates and physical response on your unit; stop built-in room demand control before scheduling it. It remains beta on other firmware and CAV configurations. Actual fan readings, monitoring, pairing and energy data are read-only. Kitchen, Fireplace and Override remain status-only. W1 stays visible as a maintenance reminder; other faults and unknown alarms still block control. Saved profile edits are persistent, not a live fan dimmer, and have no automatic return. Unequal targets do not establish pressure or provide fireplace safety. Optional room-sensor demand control still requires percentage configuration.

Feedback wanted

Please report:

1. Ventilation model and controller firmware
2. Whether pairing succeeds
3. Whether mode/profile changes work on the first tap, including linked targets and CAV units where applicable
4. Whether live W and cumulative kWh appear in Homey Energy and Insights
5. Panel 1/2 readings, active temperature target and the temperature Flow card, including the chosen panel and control method
6. Holiday start, microventilation and end behaviour, including the controller clock and firmware
7. Any error text (please remove local IP addresses before posting logs)

This app is not affiliated with or endorsed by Komfovent. The app itself is free; this topic is the initial support and beta-feedback channel.

Thanks for testing!

Trond Ole Namlos

[olwike]

Beta report – DOMEKT R 400 H, C6M FW 1.5.44.70: reads OK, all writes rejected by the app’s pre-check, but direct Modbus writes work

Unit: Komfovent DOMEKT R 400 H, rev. R1, rotary exchanger, electric post-heater
Controller: C6M rev. 5, main module FW 1.5.44.70 (panel FW 1.1.5.46), configuration R-400-H-R-AL_v2431
Homey Pro (early 2023), Homey v13.5.0
App: Komfovent C6M 1.2.1 (test), device ID 254, port 502, reserved IP

Note: my firmware (1.5.44.70) is newer than the 1.4.47.74 you verified on.

What works:

• Pairing succeeds
• All monitoring values seems live and correct
• Homey Energy shows live W and cumulative kWh
• Control panel and the Komfovent Control app work normally

What fails (Homey only):

• Every write action: mode change (Away/Normal/Intensive/Boost), Intensive profile dimmer, electric heater toggle
• Same result from the Homey device tile and from Flows
• Error text (Norwegian UI): “Aggregatet bestod ikke den nødvendige kontrollen. Ingenting ble endret.”
• Unit state during tests: manual Normal, AUTO off, ECO off, 1 active alarm (filter)

Direct Modbus test from a PC (pymodbus 3.6.9, unit ID 254) – writes work fine:

• Holding registers 0–19 before: [1, 0, 0, 0, 2, 1, 1, 1320, 0, 4, 0, 3, 0, 100, 0, 100, 300, 300, 2, 0]
• write_register(4, 3) → WriteRegisterResponse 4 => 3, isError: False
• Register 4 after: [3], and the unit switched to Intensive (confirmed in the Komfovent app)

So the unit accepts mode writes over Modbus TCP; it looks like the app’s pre-write/compatibility check is failing on this model or on FW 1.5.x.

Diagnostics report ID: 97b98141-cfa3-45b3-b259-d170298657c1

Happy to run any further tests.

Ole Benjamin

-Supported by Claude.

[Namlosen]

Thanks @olwike — that was a very useful report!

Version 1.2.5 is now available in Test:

Komfovent C6M | Homey

I found a bug in the app’s pre-check: both the public 1.2.1 and the newer local 1.2.4 blocked every active alarm, including the W1 filter-maintenance reminder. This is consistent with the problem you described. Your register excerpt does not include the actual alarm code, so I cannot yet confirm the fix on your particular R400. There is no blanket block on firmware 1.5.x; the app records and checks the firmware found during pairing.

The update includes:

• W1 filter maintenance no longer blocks normal mode, profile or reheating-permission changes. It remains visible, and filters still need attention. Other faults, unknown alarms or incomplete alarm data remain blocked.
• Clearer Norwegian and English error messages, including alarm codes.
• The previously local timeout and recovery improvements: simultaneous identical commands are combined, confirmed Modbus rejections no longer cause a permanent unknown-result lock, and a transient readback error gets one delayed read-only verification attempt. Writes are not automatically repeated.
• Profile slider edits stay in place until saving is confirmed, including when an operation fails.
• Fixes for settings changes and connection loss during an in-progress command.

The release passed 144 automated tests and Homey’s build validation. It is installed and tested on my R700, including Normal → Intensive → Normal and profile/heating checks. The R400/filter case is covered in simulation; your real-device retest is still important.

Please update the existing app to 1.2.5 without removing/re-pairing the device, then try a single Normal → Intensive → Normal cycle. Mode changes need no extra confirmation dialog; allow the running command to finish before tapping again. Existing control settings are preserved.

Could you let me know whether mode changes, profile saving and the heater-permission toggle now work? If anything still fails, please share the exact new error and the alarm code shown on the unit’s panel, without private network details. Thanks again!

Trond Ole

[olwike]

Confirmed – 1.2.5 fixes it on the R 400 H.

The active alarm on my unit was indeed W1 (clogged air filters), so your diagnosis was spot on.

Updated in place without re-pairing, all control settings preserved. Tested:

• Normal → Intensive → Normal: works, each change confirmed on the unit before the next
• Intensive profile slider: saves and applies
• Electric reheating permission toggle: works

W1 still shows in Homey as it should. No errors.

Thanks for the fast turnaround – happy to keep testing future builds on this unit.

-Ole Benjamin

[Bubiai_2]

Hi there, thank you for this great app. I’m looking into buying a Komfovent Domekt R 400 / 450 unit and was wondering if CO2 monitoring is on your roadmap for future updates.

[Namlosen]

Hi @Bubiai_2, thanks for asking!

You can already use a separate CO₂ sensor supported by Homey to automate ventilation with the current Test app. The CO₂ reading comes from that sensor’s Homey integration, and a Flow can switch the Komfovent between Normal, Intensive and Boost. I use external room sensors this way in my own setup; the thresholds and return conditions are configured in Flow.

If you mean displaying the CO₂ reading from a sensor wired directly to the Komfovent controller, that is not available in the current Test version yet. I have checked Komfovent’s C6/C6M documentation: it provides sensor type and measured-value registers, so read-only monitoring is technically feasible. I am assessing this as the next feature to add, including displaying ppm and making the readings available to Homey Insights and Flows. It will need verification with an actual connected CO₂ sensor before I can confirm support or give a release date.

The unit needs an appropriate installed/configured CO₂ sensor; the app cannot provide a real CO₂ measurement without one. For an R400/R450 purchase, please also confirm the exact controller with the supplier: this app currently targets C6/C6M. The R400 H/C6M combination has a successful beta report in this thread; I do not yet have equivalent confirmation for an R450.

Would you be using a Komfovent-connected sensor or a separate sensor already available in Homey?

Reference: https://www.komfovent.com/en/downloads/MODBUS_connection_C6_EN.pdf

Trond Ole

[Bubiai_2]

I am currently using this one: Sonoff AirGuard CO2 SAWF-08P Wifi. I just bought the new device without a CO2 sensor. I think I will add one later.

[Bubiai_2]

I’m currently setting up some flows for my R-450-V-C6M recuperator and ran into a couple of things that seem to be missing. Just wanted to check if anyone else has noticed this or found a workaround:

Flow Triggers: When creating a flow, I couldn’t find a “When…” card for “Operating mode changed”. It would be super useful to trigger actions based on that!

Insights: In the Insights section, the exhaust air temperature (EHA) isn’t showing up anywhere.

[Namlosen]

Hi @Bubiai_2, thanks for pointing these out. You’re right: both are missing from the current Test version.

I’ve started work on v1.3.0. It will add an “Operating mode changed” Flow trigger with the previous and new mode, plus a separate exhaust air temperature (EHA) reading in Insights and the dashboard. EHA will come from its own register, not the extract air temperature reading. The update will also show whether a mode was selected manually or by a Flow; that feature is currently only installed in my local setup.

I’ll test it on my PC and my own C6M unit before publishing a new Test version. I don’t have a release date yet, and this won’t mean every R450 variant has been verified. Existing devices and settings should carry over without re-pairing. Direct readings from a CO₂ sensor connected to the unit are not part of this update.

Could you share your app version and the C6M firmware on your R-450-V-C6M? That will help when we retest it. Thanks for testing!

Trond Ole

[Namlosen]

Hi @Bubiai_2, v1.3.0 is now available in Homey Test as Build 12:

Komfovent C6M | Homey

Both features you asked for are included:

• Operating mode changed in the When section of Flow for your C6/C6M device. It provides tags for the new mode, previous mode, mode number and reason. Mode tags use fixed IDs such as normal and intensive. The first reading, a restart or selecting the same mode again won’t trigger a false mode change.
• Exhaust air temperature (EHA) as a separate sensor with history in Insights, also shown in both dashboard widgets. It reads R961 rather than reusing the extract air temperature (ETA). History starts after the upgrade; older EHA readings can’t be recovered.

The update also shows why a mode was selected manually or by a Flow. You can update your existing device without re-pairing, so please don’t delete it to get the new sensor. A missing or invalid EHA reading is shown as unavailable without blocking the other controls. No new Modbus write operations have been added.

The release passed all 178 automated tests and Homey’s validation and build checks. The production dependency audit found no known vulnerabilities. On my R700/C6M, I tested Normal → Intensive → Normal with a real Flow and checked that selecting the same mode again didn’t trigger it. EHA readings and history were also confirmed in Homey. This is still a Test release, not a certified Live release or confirmation that every R450 variant works.

Could you share your C6M firmware version and let me know whether both features work on your R-450-V-C6M after updating? Thanks for helping improve the app!

Trond Ole

[Bubiai_2]

The device disconnected after about three hours of operation. For the past hour, it has been in monitoring mode only.

Module firmware C6M 1.5.50.77

App 1.3.0

3d864f14-8897-45da-861e-8bde889d6615

App restart didn’t help. Chrome shows: ‘unavailable’, and the Homey app says: ‘no response’.

Update: Flow control mode to cav. During this time, I was changing the modes.
The controller answered, but its configuration is not supported yet
(airflow control is not a percentage profile, airflow scale is not 0 to
100 percent, Away profile is outside the supported range, Normal
profile is outside the supported range, Intensive profile is outside
the supported range, Boost profile is outside the supported
range). C6/C6M percentage profiles are required

[Bubiai_2]

Flow cards: “Active fan level is greater than…” – exists. “Active fan level is less than…” – exists. “The active fan level has changed” – I think it would be really convenient to have this card. (When the fan speed is modified, it changes with a certain delay. So, I believe this card would be very useful).

When: “Recuperator turned on/off”

Great job, Namlosen.

Thank you!

Update:

Is it possible to add a card starting with: When – the remaining filter is X%?

And- airflow speed… .?!

[Namlosen]

Hi @Bubiai_2, v1.5.1 is now in Test as Build 13. Thanks for the Flow suggestions — they’re included in this update.

Install or update the Test version

The new When cards cover actual fan level changed, unit turned on/off, and filter remaining reached or fell below a chosen percentage. The filter card catches a crossing such as 51% → 49% at a 50% threshold; it doesn’t need to read exactly 50%. Initial readings, restarts and reconnects don’t generate false change events. These cards observe the unit — they don’t add a power-off command.

There are also conditions for fresh data, actual fan percentage and measured airflow. Percentage and air volume are kept separate; volume conditions need a supported CAV setup with confirmed units.

Both dashboard panels now explain missing readings and their register sources. Available panel/extract humidity and correctly typed B8/B9 CO₂ inputs are supported, but the relevant physical sensors still need to be installed and configured.

For room sensors, there’s optional, experimental continuous demand control using the saved Normal profile. It needs HomeyScript; the advanced widget now includes a device-specific setup guide and script. It’s off by default, pauses after restart and restores the saved original profile on manual takeover. Don’t run it alongside another fan-control automation.

Regarding your CAV report: an already-paired controller that answers should now stay available for monitoring rather than being marked disconnected just because percentage control is unsupported. CAV control and new CAV pairing are still not supported. This doesn’t prove the cause of the original three-hour disconnect, so I’d appreciate another longer-running check on your R450.

This went through three test/review rounds and an extra final run, with 233 automated tests passing. The new event edge cases were tested in simulation; the upgrade and live readings were checked on my R700. Please update in place without removing your device, and let me know how the new cards and connection behave. Model, firmware, app version and the exact error text are especially helpful. Please leave private network details out of public logs.

Thanks again for testing!

Trond Ole

[Bubiai_2]

Start 14.05

Tested Flow control mode CAV

14.50

16.44

17.37 end test. Flow control mode off

The app’s flow control mode is CAV, and it runs stably in monitoring mode. Now we need the control functionality! .

When flow control mode is OFF,

switches to manual fan control (active supply target). It’s difficult to match the exact same percentages. Maybe we shouldn’t control them separately?!

Super

[Namlosen]

Hi @Bubiai_2, thanks for the longer test and the graphs — good to hear that CAV monitoring stayed stable. I’ve added the controls you asked for in v1.6.0, now available in Test as Build 14.

Install or update the Test version

The new linked profile target is available in the device, the advanced Dashboard widget and Flow. It moves both saved targets together while keeping their existing ratio, allowing for whole-unit rounding. For example, 300/270 m³/h becomes 420/378 when scaled up by 40%; it doesn’t force both sides to the same value. There is still a separate-target option when you deliberately want an imbalance.

CAV control is experimental and off by default. Update the existing device without re-pairing, check the units and limits, then enable Enable experimental CAV control in the device settings alongside the ordinary/advanced control settings you need. It uses the controller’s configured m³/h or l/s targets and separate maximum capacities; it doesn’t change the airflow configuration or units. A dedicated CAV Flow action keeps volume commands separate from the older percentage actions. The built-in room-sensor demand controller still requires percentage configuration; CAV automation can use external-sensor Flows with the new actions.

One important detail: these controls change the saved profile, not a temporary override. There is no automatic timer or return. Unequal targets aren’t proof of positive pressure and don’t activate the controller’s dedicated Fireplace function. Restore the intended targets after using an imbalance.

This release went through three test/review rounds and a fourth final run, with 259 automated tests passing in the final run, a clean production dependency audit and Homey validation/build checks. On my R700, I also checked linked control, separate targets and restoration on the inactive Away profile while Normal was left unchanged. My unit uses percentage control, so this is not yet physical confirmation of CAV writes on your R450, or proof that the original disconnect has been resolved.

Could you try a small change within your commissioned limits and check both targets on the panel, then restore them? I’d appreciate reports from other models too. Please include the app version, model, firmware, units and exact error text if anything fails, but leave private network details out of public logs.

Thanks again for helping test this!

Trond Ole

[Bubiai_2]

7e10f6d0-0725-4125-b40b-9b88390fb678

Update:

Linked profile target preserve balance" (with flow mode off in this case) works perfectly. I liked it

Update

If possible, please add a THEN card: ‘Set Electric heater Temperature to …°C’"

[Hans_Timmermans]

Hi. Thanks so much for this app. I have to Komfovents (one R400 and one R450) with the C6M panels in my home. They run on the latest firmware (main module: 1.4.50.77; panel software: 1.1.5.53) with reserved ip-addresses.

I am running the latest test version, which operates just great. .

For some reason one C6M is installed as panel 1 and the other as panel 2.

I am interested in seeing the actual room temperature as measured by the panel in combination with the set temperature (of the actual mode). I couldn’t find those parameters in the settings app.

Is it possible to add those or is there a reason why they are not included. I need to be able to select the temperature of panel 1 or 2.

Thanks a lot!

Hans Timmermans

[Bubiai_2]

Just stopping by to dust things off and disturb your peace!

How’s it going?

[Namlosen]

Good timing, @Bubiai_2 — v1.8.0 is now available in Homey Test as Build 17. It has also been submitted for review; it is not a Live release yet. Thanks to you and @Hans_Timmermans for the suggestions.

This update adds the C6M panel temperatures, a choice of Automatic / Panel 1 / Panel 2 in the device settings, and the temperature target for the mode actually running. The device page has both panel readings when available; Compact and Advanced show the chosen panel and active target. Mini stays small and keeps its mode buttons and reheating-permission switch. A missing panel shows no reading rather than borrowing a value from somewhere else. Choosing a panel in Homey only changes the display, not the unit’s control sensor.

There is also a new THEN card: Set ventilation temperature target. It stores a target for Away, Normal, Intensive or Boost, or the currently active standard profile. The range is 5–40 °C in 0.1 °C steps. Enable ordinary control, advanced profile control and the separate profile-temperature setting to use it. This is the ventilation profile’s setpoint, not the heating element’s temperature: it does not switch modes or turn heating on.

The release passed three full test-and-review rounds. On my R700, I checked the inactive Away target from 20.0 to 20.1 °C and back, with readback from the controller, and checked panel 1 and missing-panel handling. I still need reports from a real panel 2, the other profiles and temperature-control methods. Physical CAV writes also remain unconfirmed. For the earlier CAV error, the diagnostic showed the CAV control gate was closed before a write was sent; CAV needs its separate experimental setting as well as ordinary and advanced control. That does not explain or resolve the original three-hour disconnection.

Existing devices, Flows and saved profiles are kept; no re-pairing is needed. If you try the temperature features, please share the model, firmware, app version, selected panel and control method, plus any exact error text. Please leave private network details out of logs. @Hans_Timmermans, a check of both of your panel arrangements would be especially useful.

I’m also looking into a timed cooking/airing boost and proper cooker-hood or fireplace assistance. Those are separate jobs and are not included in 1.8; simply raising both fans is not the same as compensating for an extractor or confirming pressure in the house.

[Hans_Timmermans]

L.S..

As requested I have generated a diagnostic report. You need a code:

Ce689276-4e22-45a0-8a95-91de4fab2ac2

As far as I can see it works wonderful. Thank you so much! Both panel 1 and 2 are correctly represented. What I don’t understand is the second screen. It makes little sense using it as is.

Kind regards,

Hans Timmermans