Set V40 min

Use this action to set the minimum quantity of water at 40°C for a water heater. When the available capacity drops below this value, the heater turns on to guard against running out of warm water.

Using this action from the user interface

If you prefer building automations and scripts visually, Home Assistant walks you through this action step by step. You pick what to target, tweak a few options, and save. No YAML knowledge required.

To set the minimum quantity from an automation or a script:

1. Go to Settings > Automations & scenes.
2. Open an existing automation or script, or select Create automation > Create new automation.
3. If you’re setting up a new automation, add a trigger in the When section. Scripts don’t need a trigger. They run when something else calls them.
4. In the Then do section, select Add action.
5. Select what you want to control. Under By target (see Targets), select the water heater you want to set.
6. From the actions shown for that target, select OSO Energy: Set V40 min.
7. Set the V40 min value you want to apply.
8. Select Save.

Options in the UI

Using this action in YAML

If you work directly in YAML, or you want to know exactly what Home Assistant does under the hood, this section has the technical reference. It lists the field names you use in YAML, their types, and which ones are required.

In YAML, refer to this action as osoenergy.set_v40_min. A basic example looks like this:

action: osoenergy.set_v40_min
target:
  entity_id: water_heater.heater
data:
  v40_min: 240

This sets the minimum quantity of water at 40°C to 240 liters.

Options in YAML

Targets of the action

This action requires a target. The target is the object of the action. You can point the action at a single entityAn entity represents a sensor, actor, or function in Home Assistant. Entities are used to monitor physical properties or to control other entities. An entity is usually part of a device or a service. [Learn more], a device, an area, a floor, or a label, and Home Assistant will run the action on every matching water_heater entity behind that target.

• Entity: one specific water_heater entity, such as water_heater.living_room.
• Device: every water_heater entity that belongs to a device.
• Area: every water_heater entity in a room or area.
• Floor: every water_heater entity on a floor.
• Label: every water_heater entity that shares a label.

You can also select different target types in one action. For example, you can add a specific entity and an area as targets in the same action to run the action on both of them at once.

Try it yourself

Ready to test this? Open Developer tools > Actions, search for this action, fill in the fields, and select Perform action. You see what happens on your actual entitiesAn entity represents a sensor, actor, or function in Home Assistant. Entities are used to monitor physical properties or to control other entities. An entity is usually part of a device or a service. [Learn more] without writing a line of YAML.

Still stuck?

The Home Assistant community is quick to help: join Discord for real-time chat, post on the community forum with the action you’re calling and what you expected to happen, or share on our subreddit /r/homeassistant.

Related actions

These actions work well alongside this one:

• Turn on heating: Turns on heating for an OSO Energy water heater.

• Turn off heating: Turns off heating for an OSO Energy water heater.