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

Apps
1

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

Updated 9 September 2026: Test version 1.2.5 is available. It fixes W1 filter reminders blocking control and includes the newer stability/recovery improvements. Release details and beta-test follow-up.

Install the Test version: Komfovent C6M | Homey

What is included

  • One-tap modes: Away, Normal, Intensive and Boost
  • Native percentage sliders and separate supply/extract targets for all four saved standard profiles (20–100%)
  • Profile-specific electric reheating permission, separate from actual heater output
  • Live fan levels, temperatures, filter life, alarms and unit status
  • Native Homey Energy support with live power in W and total consumption in kWh
  • Automatic Insights history and standard Energy Flow triggers
  • Two adaptive Homey Dashboard widgets
  • Flow actions and conditions for automation from other smart-home devices
  • Fully local Modbus TCP communication; no vendor cloud account or analytics

Compatibility

The current physical beta is verified on 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.

Other C6/C6M combinations may work, but I would like real-world beta reports before expanding the compatibility statement.

Control scope

The app writes only the four documented standard modes, complete supply/extract pairs for their saved profiles, and profile-specific reheating permission. Changes use exact readback verification. Actual fan readings, monitoring, pairing and energy data are read-only. Kitchen, Fireplace and other special modes are observed, not written. W1 remains a visible maintenance reminder; other faults and unknown alarm states still block control.

Feedback wanted

Please report:

  1. Ventilation model and controller firmware
  2. Whether pairing succeeds
  3. Whether mode/profile changes work on the first tap
  4. Whether live W and cumulative kWh appear in Homey Energy and Insights
  5. 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

2

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.

3

Thanks @olwike — that was a very useful report!

Version 1.2.5 is now available in Test:

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

4

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