# \[APP\]\[PRO\] wMBUS Water Meter — Kamstrup Multical 21 / FlowIQ 2200

**URL:** <https://community.homey.app/t/app-pro-wmbus-water-meter-kamstrup-multical-21-flowiq-2200/154911>\
**Category:** Apps\
**Tags:** app\
**Created:** [May 15, 2026, 6:51am UTC](https://community.homey.app/t/app-pro-wmbus-water-meter-kamstrup-multical-21-flowiq-2200/154911 "2026-05-15T06:51:17Z")\
**Posts on this page:** 1\
**Page:** 1

<div class="post-metadata">

**Author:** ![Kasper\_Mansson](https://sea1.discourse-cdn.com/flex025/user_avatar/community.homey.app/kasper_mansson/32/123241_2.png) [@Kasper\_Mansson](https://community.homey.app/u/Kasper_Mansson)\
**Post date:** [May 15, 2026, 6:51am UTC](https://community.homey.app/t/app-pro-wmbus-water-meter-kamstrup-multical-21-flowiq-2200/154911/1 "2026-05-15T06:51:17Z")

</div>

A community Homey Pro app that decodes encrypted wMBUS telegrams from  
Kamstrup Multical 21 and FlowIQ 2200 water meters via MQTT, and exposes  
them as fully-featured Homey devices with leak/burst alarms, flow rate,  
flow temperature, and Energy dashboard integration.

## Features

- AES-128-CTR decryption (ELL II, CI=0x8D) with CRC-16/EN-13757 verification
- Status flags: dry, reversed, leaking, bursting (exact bit mapping from wmbusmeters)
- Capabilities:
  - `meter_water` — total consumption (m³), integrated with Homey Energy
  - `measure_water` — current flow rate (L/min, derived from delta)
  - `measure_temperature` — flow temperature (°C, when available)
  - `alarm_water` — main leak/burst alarm
  - `alarm_water.dry` — dry pipe (separate, non-critical)
  - `alarm_water.reversed` — reversed flow (separate, non-critical)
  - `alarm_water.bursting` — pipe burst (separate)

- App-level MQTT configuration (broker URL, credentials, topic)
- Device class `watermeter` — shows up in Homey Energy dashboard
- Full Danish + English localization

## Requirements

- Homey Pro (firmware ≥ 5.0.0)
- An MQTT broker reachable from Homey (e.g. MQTT Server app on Homey itself)
- A wMBUS radio gateway publishing raw hex frames to MQTT
  - Reference implementation: Heltec LoRa32 V3 + ESPHome (firmware available in repo)
  - Compatible with any gateway that forwards raw hex telegrams

- AES-128 key for your meter (request it from your water utility)

## Installation (current — via CLI)

git clone [GitHub - KMaansson/com.koledanmark.wmbus: kamstrup multical 2200 water m3 to homey · GitHub](https://github.com/KMaansson/com.koledanmark.wmbus.git)  
cd com.koledanmark.wmbus  
npm install  
homey app install

Submitting to Homey Community Store soon — will update this thread when available.

## Repository & Documentation

- Source: [GitHub - KMaansson/com.koledanmark.wmbus: kamstrup multical 2200 water m3 to homey · GitHub](https://github.com/KMaansson/com.koledanmark.wmbus)
- Full setup guide (Danish): included in the repo

## Hardware tested

- Kamstrup Multical 21, T1 mode, 868 MHz (Denmark — Greve Vandværk)
- Should work with any MC21 / FlowIQ 2200 broadcasting T1 telegrams

## Status

Stable. Running 24/7 in my own setup since May 2026.

## Feedback

Please report bugs and feature requests via GitHub Issues:

> **[Issues · KMaansson/com.koledanmark.wmbus](https://github.com/KMaansson/com.koledanmark.wmbus/issues)**
>
> kamstrup multical 2200 water m3 to homey. Contribute to KMaansson/com.koledanmark.wmbus development by creating an account on GitHub.