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Controlling the speed of a fan

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Arjen Hiemstra edited this page Dec 7, 2023 · 5 revisions

Two ways to control the speed

There are two ways to influence the speed of itho fan devices. (towards the itho firmware, either via the add-on or any other source!):

  • type 1 - Stepless via PWM2I2C command (ie. slider/buttons on the add-on website, part of the API commands, speed commands to the itho/cmd topic)
  • type 2 - Remote commands like high, med, low etc. (via virtual remote or RF remote directly joined to the itho)

Limitations

Type 1 only works if:

  1. the itho is in medium or auto mode
  2. if your itho model is a CVE device or HRU200.

Type 2 only works if:

  1. the specific itho device supports remotes
  2. if the (virtual) remote is joined to the itho.

There are many (more advanced) combinations possible to achieve a specific setup (depending on your goals) but everything ends up in either a type 1 command or type 2 command.

Help! A speed command does not work!

If a type 1 command does not work, the itho is almost always not in the auto or medium mode setting. To check this:

  • go to the webpage of the add-on
  • go to "itho status"
  • look for the label "FanInfo" (or "Selection" on older blue lid itho models). The value should be "auto", "medium" or "3". (if "FanInfo" is not available, activating the I2C function 31DA should solve this)

The correct mode setting can be forced by sending a type 2 auto or medium command before a type 1 command. The origin of this command can be either a physical remote or a virtual remote.

This medium/auto/3 mode setting can be automated by switching on the "Force medium mode" option. For this to work, make sure the virtual remote with index 0 is registered with your itho.

Help! Fan won't go lower than ie. 30%!

Probably you have a newer itho model with built-in humidity sensor.

Those units have a standard minimum ventilation level in auto mode of 20% or 30%. This minimum level can be changed by altering the setting: "Minimum ventilation level in Auto (%)" on the "Itho settings" page of the add-on from 20 or 30 to 0. This will greatly reduce the minimum speed value.

To be able to regulate the motor further (down to 0) you can switch the setting "Additional sensor support" to "on" on the "System settings" page of the add-on.

This will disable the humidity sensor in the itho firmware. Readouts are still possible through the add-on though.

Created By Arjen Hiemstra.

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