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“FO” shows in the heater´s display. What does it mean?

Updated over a month ago

The heater has an “open window” function that activates as soon as the detected room temperature drops more than 5 degrees within 15 minutes. The heater will automatically stop heating, and “FO” will be displayed on the heater’s screen.

In “open window” mode, the heater maintains a temperature 5 degrees above freezing (to prevent frost damage). If the temperature increases by at least 3 degrees within 15 minutes, the unit will resume heating.

For Generation 3 heaters, follow the steps below to enable/disable the “open window” function:

To return the heater to normal mode, press the function button once.

To activate or deactivate the “open window” function, press and hold the function button for 3 seconds. You can also control this feature from the app if your heater is connected to WiFi.

The heater will remain in “open window” mode for a maximum of 1 hour, after which it will return to normal heating mode.

For Generation 3M heaters, follow these steps:

  • Press the menu button to enter the menu.

  • Use the + and - buttons to navigate until you see “Fo” on the display.

  • Press the button to enter the open window mode.

  • Use the + or - button to select “On” or “Off.”

Confirm your choice by pressing the button. You can also enable/disable the open window function from the app if you’re connected to Wi-Fi.

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