Add dual heating support

.github/copilot-instructions.md

@@ -211,8 +211,26 @@ Test fixtures (JSON responses) are in `tests/fixtures/`
 
 ## Common Tasks
 
+### Fetching Parameters from a Real Device
+
+Use `examples/fetch_param.py` to query raw parameter data from a real BSB-LAN device before adding new parameters:
+
+```bash
+# Set your device connection details
+# Leave BSBLAN_HOST unset to use auto-discovery, or set it explicitly:
+export BSBLAN_HOST="192.168.1.100"
+export BSBLAN_PASSKEY=your_passkey  # if needed
+
+# Fetch one or more parameters
+cd examples && python fetch_param.py 1645
+cd examples && python fetch_param.py 1645 1641 1642 1644 1646
+```
+
+The output shows the raw JSON response including value, unit, description, and data type — use this to determine the correct model field type and naming.
+
 ### Adding a New Settable Parameter
 
+0. Fetch the parameter from a real device using `examples/fetch_param.py` to inspect the raw response
 1. Add parameter ID mapping in `constants.py`
 2. Add field to appropriate model in `models.py`
 3. Add parameter to method signature in `bsblan.py`

.github/skills/bsblan-parameters/SKILL.md

@@ -14,6 +14,57 @@ This skill guides you through adding new parameters to the python-bsblan library
 - Legionella-related parameters use `legionella_function_*` prefix
 - DHW (Domestic Hot Water) parameters use `dhw_*` prefix
 
+## Discovering Parameters from a Real System
+
+Before adding a new parameter, use `examples/fetch_param.py` to retrieve the raw API response from a real BSB-LAN device. This shows the exact structure, data types, units, and descriptions returned by the device.
+
+### Setup
+
+```bash
+# Set environment variables for your device
+export BSBLAN_HOST=<ip-or-host>     # Your BSB-LAN IP address; leave unset to use autodiscovery
+export BSBLAN_PASSKEY=your_passkey  # Optional: if your device requires a passkey
+export BSBLAN_USER=username         # Optional: if authentication is enabled
+export BSBLAN_PASS=password         # Optional: if authentication is enabled
+export BSBLAN_PORT=80               # Optional: defaults to 80
+```
+
+### Fetching Parameters
+
+```bash
+# Fetch a single parameter
+cd examples && python fetch_param.py 1645
+
+# Fetch multiple parameters at once
+cd examples && python fetch_param.py 1645 1641 1642 1644 1646
+```
+
+### Example Output
+
+The raw API response shows the exact structure you need to model:
+
+```json
+{
+  "1645": {
+    "name": "Legionella function setpoint",
+    "value": "70.0",
+    "unit": "°C",
+    "desc": "",
+    "dataType": 0
+  }
+}
+```
+
+Use this output to determine:
+- **Field type**: `float`, `int`, or `str` based on the `value` format
+- **Unit**: The `unit` field (e.g., `°C`, `%`, `-`)
+- **Description**: The `name` field for docstrings
+- **Data type**: The `dataType` field for `EntityInfo` typing
+
+### Device Discovery
+
+`fetch_param.py` uses mDNS/Zeroconf discovery (via `examples/discovery.py`) to find your BSB-LAN device automatically when `BSBLAN_HOST` is not set. If mDNS is unavailable, set the `BSBLAN_HOST` environment variable directly.
+
 ## Steps to Add a New Parameter
 
 ### 1. Add to `constants.py`