What CO2 means

CO2 is shown in parts per million, or ppm.

Indoor CO2 rises when people breathe in an enclosed space and ventilation is limited. Outdoor air is usually much lower than crowded indoor spaces, so CO2 can help you understand ventilation.

Before assuming the CO2 reading is wrong:

• Let the monitor run for a while after power-on.
• Keep the monitor away from direct breath.
• Place it where air can move freely around the monitor.
• Compare changes over time instead of reacting to one short reading.

CO2 can rise quickly near people, in small rooms, or near poor ventilation.

When to calibrate

Use CO2 calibration only when you intend to recalibrate the CO2 reading. Calibrate only in fresh outdoor air, when the expected CO2 level is close to ambient outdoor conditions.

Do not calibrate:

• while someone is breathing directly near the monitor
• in a crowded or poorly ventilated room
• immediately after moving the monitor from one environment to another
• just because a reading is temporarily higher than expected

Start CO2 calibration from the monitor

The monitor includes a CO2: Calibrate action in Settings.

To start the action:

• Move the monitor to a suitable calibration location.

• Unlock the monitor.
• Press Menu/Select to open the main menu.
• Use Up or Down to select Settings.
• Press Menu/Select.
• Select CO2: Calibrate.
• Confirm the action only if you are ready to calibrate.

If CO2 looks too high

Try the following:

• Move the monitor away from direct breath.
• Ventilate the space and watch whether CO2 decreases.
• Compare readings in different rooms.
• Let the monitor stabilize after a location change.
• Check whether the monitor is near people, pets, combustion sources, or enclosed spaces.

If CO2 does not change

Try the following:

• Keep the monitor powered on and wait for new readings.
• Move the monitor to a different environment.
• Check whether other readings are updating.
• Restart the monitor if readings appear frozen.

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