Monitor whether your heating valve is open or closed in Home Assistant using a Belimo SR230A-R actuator, a Belimo S1A auxiliary switch add-on, and a Shelly 1 Mini Gen4.
The lovelace Card created in this repo is then part of a bigger dashboard providing an overview of the whole heating sytem, driven by a Hoval Toptronic: https://github.com/vincentmakes/canbus_hoval
The lovelace card by itself (valve in open position), and the real valve (in closed position this time)
The Belimo SR230A-R is a rotary actuator commonly used on ball valves in heating systems. It has no built-in position feedback — only a mechanical position indicator (the black handle). By adding the Belimo S1A auxiliary switch module, we get a dry contact that changes state based on valve position. A Shelly 1 Mini Gen4 reads that contact and exposes it to Home Assistant as a binary sensor. The Belimo S2A is also an option in case the S1A is not available.
The result: a binary_sensor in HA that tells you whether your heating valve is open or closed, with custom SVG illustrations of the actual actuator.
| Component | Description | Approx. Cost |
|---|---|---|
| Belimo SR230A-R-9 | Rotary actuator (RetroFIT+), 20 Nm, AC 100–240 V, Open/Close, 3-point | (existing) |
| Belimo S1A | Auxiliary switch 1× SPDT, add-on for SR-A actuators | ~€50 |
| Shelly 1 Mini Gen4 | Compact smart relay — WiFi, Zigbee, Matter, Bluetooth | ~€15 |
The S1A is officially listed as a compatible electrical accessory in the Belimo SR230A-R datasheet (accessories section, page 3–4). It clips directly onto the position indicator of the actuator housing.
The S1A attaches onto the position indicator (handle mechanism) of the SR230A-R actuator. The guiding grooves between the housing and the switch ensure a tight fit.
Steps:
- Power off the actuator (de-energize the 230V supply)
- Briefly remove the position indicator lever
- Slide the S1A module into the grooves on the actuator housing
- Reattach the position indicator lever
- Set the switching point using the S1A adjustment dial
- Power back on
⚠️ Important: All settings on the S1A must be done with the actuator de-energized. Since you are working near 230V mains wiring, installation should be performed by a qualified electrician.
The S1A has 3 wires:
| Wire | Color | Function |
|---|---|---|
| S1 | Violet | Common |
| S2 | Red | Normally Open (NO) |
| S3 | Grey | Normally Closed (NC) |
Use S1 and S2 (NO) if you want: contact closed = valve open. Use S1 and S3 (NC) for the inverse logic.
The Shelly 1 Mini Gen4 is used purely as a sensor (not switching anything with the relay). The S1A dry contact passes mains voltage through to the Shelly's SW input when closed.
┌─────────────────────────┐
│ Shelly 1 Mini Gen4 │
│ │
Mains L ──────┬─────┤ L │
│ │ │
│ │ N ─────────┬─────────── Mains N
│ │ │ │
│ │ SW ────┐ │ │
│ │ │ │ (O and I │
│ └────────┼───┘ unused) │
│ │ │
│ S1A Contact │
│ │ │
│ S2 (Red) ┘ │
│ │
└──── S1 (Violet) ───────────────┘
S1A Aux Switch
In plain terms:
- Power the Shelly: connect Mains L → Shelly L and Mains N → Shelly N
- Wire the S1A: connect Mains L → S1A S1 (Violet/Common)
- Bridge the contact to Shelly: connect S1A S2 (Red/NO) → Shelly SW
When the valve opens, the S1A contact closes, passing 230V from L to SW — the Shelly reads "on". When the contact opens, SW floats — the Shelly reads "off".
⚠️ Safety: You are routing mains 230V through the S1A contact. Use proper Wago connectors and keep all connections inside a junction box. The S1A contact is rated for 250V AC.
The O and I terminals on the Shelly are not used — those are for the relay output side.
After powering the Shelly and connecting it to your WiFi network:
- Open the Shelly web interface or app
- Go to Settings → Input/Output Settings
- Set Input mode to Switch (not Button)
- Set Relay mode to Detached — so the switch input is reported as a sensor only and doesn't toggle the relay
The Shelly integration in Home Assistant will auto-discover the device and expose the input as a binary_sensor.
Add this to your configuration.yaml to create a friendly sensor with a proper device class. Replace the entity ID with your actual Shelly input entity (check Settings → Devices → Shelly 1 Mini Gen4):
template:
- binary_sensor:
- name: "Heating Valve"
unique_id: belimo_heating_valve
device_class: running
state: >
{{ is_state('binary_sensor.shelly_1_mini_gen4_input', 'on') }}This project includes custom SVG illustrations of the Belimo SR230A-R-9 actuator showing the valve in open and closed positions.
-
Copy the SVG files to your HA
config/www/folder:belimo_v8_open.svgbelimo_v8_closed.svg
-
Files in
config/www/are served under/local/in HA.
Tip: If images don't appear, restart HA or clear your browser cache.
Add this card to your dashboard via the YAML editor. This uses a vertical-stack with card-mod for styling:
type: vertical-stack
cards:
- type: picture-entity
entity: binary_sensor.shelly_1_mini_gen4_input
name: Heating Valve
show_state: false
show_name: false
state_image:
"on": /local/belimo_v8_open.svg
"off": /local/belimo_v8_closed.svg
unavailable: /local/belimo_v8_open.svg
unknown: /local/belimo_v8_open.svg
card_mod:
style:
.: |
ha-card {
background: rgba(200, 200, 200, 0.3);
}
hui-image $: |
img {
max-height: 400px !important;
object-fit: contain !important;
}
- type: entities
entities:
- entity: binary_sensor.shelly_1_mini_gen4_input
name: Valve Status
icon: mdi:valve
- type: attribute
entity: binary_sensor.shelly_1_mini_gen4_input
attribute: last_changed
name: Since
icon: mdi:clock-outline
format: relative
- type: history-graph
entities:
- entity: binary_sensor.shelly_1_mini_gen4_input
name: Heating history
hours_to_show: 24
show_names: falseNote: This card requires card-mod installed via HACS. If you don't want to install card-mod, remove the
card_mod:section — the card will still work, just without the size/background customization.
If you're using the newer Sections dashboard layout, vertical-stack works fine. Add the card via the YAML editor in the card picker dialog.
A simpler version that works without any custom components:
type: vertical-stack
cards:
- type: picture-entity
entity: binary_sensor.shelly_1_mini_gen4_input
show_state: false
show_name: false
state_image:
"on": /local/belimo_v8_open.svg
"off": /local/belimo_v8_closed.svg
unavailable: /local/belimo_v8_open.svg
unknown: /local/belimo_v8_open.svg
- type: history-graph
entities:
- entity: binary_sensor.shelly_1_mini_gen4_input
name: Heating
hours_to_show: 24
show_names: falsebelimo-ha-valve-monitor/
├── README.md
├── images/
│ ├── ha-card-preview.png # Screenshot of the card in HA
│ ├── belimo-front.jpg # Photo of the actual installation
│ ├── belimo-angle.jpg # Photo from angle
│ └── belimo-closeup.jpg # Close-up of the actuator label
├── svg/
│ ├── belimo_v8_open.svg # Valve open illustration
│ └── belimo_v8_closed.svg # Valve closed illustration
├── ha-config/
│ ├── card.yaml # Dashboard card YAML
│ ├── card-simple.yaml # Card without card-mod dependency
│ └── template-sensor.yaml # Template binary sensor
└── LICENSE
The SVG illustrations are hand-crafted vector graphics based on the actual Belimo SR230A-R-9 installation. They show:
| Closed | Open |
 |
 |
- Handle horizontal (perpendicular to pipe) = Closed / Heating Off
- Handle vertical (aligned with pipe) = Open / Heating On
- Green flow arrows when open, red X when closed
- Accurate representation: orange Belimo body, grey housing, silver unions, white insulated pipe
Once you have the valve state in HA, you can:
- Notify when heating turns on/off
- Track daily heating hours via the history integration
- Correlate heating activity with room temperature sensors
- Dashboard showing heating cost estimates based on run time
- Alert if heating hasn't turned on during cold weather (possible fault)
Example automation — notify when heating starts:
automation:
- alias: "Notify Heating On"
trigger:
- platform: state
entity_id: binary_sensor.shelly_1_mini_gen4_input
to: "on"
action:
- service: notify.mobile_app_your_phone
data:
title: "Heating"
message: "Heating valve opened"- Belimo — SR230A-R actuator and S1A auxiliary switch
- Shelly — 1 Mini Gen4 smart relay
- Home Assistant — Home automation platform
- card-mod — Custom CSS styling for HA cards
MIT License — see LICENSE for details.