OWB Monitor - Home Assistant

The OWB monitor publishes sensor data via MQTT. From v1.0.17+, entities are auto-discovered by Home Assistant via MQTT discovery - no manual YAML needed. Entities appear automatically under Settings - Devices & Services - MQTT after the node connects.

Auto-discovery is enabled by default (mqtt.ha_discovery: true). No manual YAML needed - entities appear automatically.

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Prerequisites

• OWB node flashed and online (thesada-fw v1.1.0+)
• Mosquitto MQTT broker running
• Telegram bot configured (optional, for alerts)

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1. MQTT Sensor Config

Entities auto-discovered (v1.1.0+):

Entity	Type	Description
House Supply	temperature	House loop supply (C)
House Return	temperature	House loop return (C)
Barn Supply	temperature	Barn loop supply (C)
Barn Return	temperature	Barn loop return (C)
House Pump	current	House pump RMS current (A)
Barn Pump	current	Barn pump RMS current (A)
House Pump Power	power	House pump power (W)
Barn Pump Power	power	Barn pump power (W)
Battery	battery	Battery level (%)
Battery Voltage	voltage	Battery voltage (V)
Battery Charge State	text	Charging / Discharging
WiFi RSSI	signal_strength	WiFi signal (dBm, diagnostic)
WiFi SSID	text	Connected network (diagnostic)
WiFi IP	text	Device IP address (diagnostic)

Each sensor publishes on its own topic (e.g. thesada/owb/sensor/temperature/house_supply). Availability via LWT on thesada/owb/status. WiFi diagnostics are disabled by default in HA.

Verify the node is publishing:

mosquitto_sub -h YOUR_BROKER -p 8883 \
  -u mqtt-user -P YOUR_PASSWORD \
  --capath /etc/ssl/certs \
  -t 'thesada/owb/#' -v

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2. Firmware Alerts vs HA Automations

The firmware sends alerts directly to Telegram via the Bot API when configured with bot_token and chat_ids. Alert logic lives in /scripts/rules.lua on the device (Lua-driven, hot-reloadable). See Alerts & Webhook for details.

HA automations are a second layer - useful for:

• Cross-sensor logic (e.g. supply/return delta)
• Time-based conditions (heating season only)
• Telegram /temp command responses

Both can run simultaneously.

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3. Alert Automations (HA)

Three automations cover conditions the firmware alerts don’t handle well (cross-sensor, time-based). Create each via Settings - Automations - Create Automation - Edit in YAML.

Replace notify.YOUR_NOTIFY_ENTITY with your Telegram notify entity.

Supply Temperature Low

alias: OWB Supply Temp Low
description: Alert when boiler supply drops below 40C
trigger:
  - platform: numeric_state
    entity_id: sensor.owb_house_supply
    below: 40
action:
  - action: notify.YOUR_NOTIFY_ENTITY
    data:
      message: >-
        OWB Alert: Supply temp low -
        {{ states('sensor.owb_house_supply') | round(1) }}C. Check fire.
mode: single

Loop Delta Collapsed

alias: OWB Loop Delta Low
description: Alert when supply/return delta collapses below 5C
trigger:
  - platform: template
    value_template: >
      {{ (states('sensor.owb_house_supply') | float -
          states('sensor.owb_house_return') | float) < 5 }}
    for: "00:05:00"
action:
  - action: notify.YOUR_NOTIFY_ENTITY
    data:
      message: >-
        OWB Alert: House loop delta low.
        Supply: {{ states('sensor.owb_house_supply') | round(1) }}C
        Return: {{ states('sensor.owb_house_return') | round(1) }}C
mode: single

Pump Current Zero

alias: OWB Pump Current Zero
description: Alert when pump stops during heating season
trigger:
  - platform: state
    entity_id: binary_sensor.owb_house_pump_running
    to: "off"
  - platform: state
    entity_id: binary_sensor.owb_barn_pump_running
    to: "off"
condition:
  - condition: numeric_state
    entity_id: sensor.owb_house_supply
    above: 25
  - condition: template
    value_template: >
      {{ now().month >= 9 or now().month <= 5 }}
action:
  - action: notify.YOUR_NOTIFY_ENTITY
    data:
      message: >-
        OWB Alert: {{ trigger.to_state.attributes.friendly_name }} stopped.
        Supply: {{ states('sensor.owb_house_supply') | round(1) }}C.
        Possible pump failure.
mode: single

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4. Telegram Bot Commands

alias: OWB Telegram /temp
description: Reply to /temp with current OWB readings
trigger:
  - platform: event
    event_type: telegram_command
    event_data:
      command: /temp
action:
  - action: notify.YOUR_NOTIFY_ENTITY
    data:
      message: >-
        OWB Readings:

        House: {{ states('sensor.owb_house_supply') | round(1) }} / {{ states('sensor.owb_house_return') | round(1) }}C
        Barn:  {{ states('sensor.owb_barn_supply') | round(1) }} / {{ states('sensor.owb_barn_return') | round(1) }}C
        Battery: {{ states('sensor.owb_battery_percent') }}% {{ states('sensor.owb_battery_charging') }}
mode: single

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5. Dashboard

TODO: OWB dashboard YAML to be added after first real data is collected on site.