Levenhuk Wezzer PLUS LP90
CO2 Monitor

User Manual

Wezzer PLUS

button parts

jack plug

  1. CO2 scale
  2. Current CO2 reading (ppm)
  3. Temperature
  4. SET button
  5. Humidity
  6. UP button
  7. DOWN button
  8. ALERT button
  9. MAX./MIN. button
  10. Backlight button
  11. 3.5mm DC jack

Levenhuk Wezzer PLUS LP90 CO2 Monitor

The kit includes: CO2 monitor, USB cable, user manual, and warranty.

Caution! Please remember that mains voltage in most European countries is 220–240V. If you want to use your device in a country with a different mains voltage standard, remember that use of a converter is absolutely necessary.

Getting started
Connect the power cable to the device and the DC adapter (not included) via a USB plug and connect it to the AC power supply. Relevant CO2 data will be displayed within 2.5 minutes.

Button panel and device settings
CO2 readings

ATTENTION! When the CO2 level exceeds 2400 ppm, the caution icon icon starts flashing.

400—600ppm green zone

normal outdoor air CO2 level

601—1400ppm cyan zone

typical level for occupied spaces with good air exchange

1401—1900ppm yellow zone

ventilation is recommended

1901—2400ppm red zone

ventilation strongly recommended


is associated with such symptoms as headache, sleepiness, poor attention, increased heart rate, and  nausea

> 5000ppm

serious oxygen deprivation that may lead to brain damage, coma, and death

CO2 and humidity settings

Press and hold the SET button to enter the settings. The digits that are to be set are flashing. Press UP or DOWN to change  the value.

The setting order: low CO2 alert level > high CO2 alert level > low RH% alert level > high RH% alert level. When the CO2 or humidity value reaches the set high or low alert level, the or icon appears and starts flashing.

Acoustic alert Press the ALERT button to turn the CO2 alarm on. Press the button again to disable the sound alarm.


Press the MAX./MIN. button to display the MAX. and MIN. records.

Display order: MAX. CO2 level > MIN. CO2 level > mean CO2 value within 15 minutes> mean CO2 value within 8 hours. Press and hold the MAX./MIN. button to clear the history records.


Press the UP button to switch between °C and °F.


Operating CO2 range


Air humidity, units of measurement

% (RH)

Operating humidity range

20… 95%

Temperature, units of measurement

°F, °C

Operating temperature range

0… +50°C (+32… +122°F)


color, with an LED backlight

Power supply

AC/DC adapter 5V 500mA (not included)

USB cable

1.5m (4.9ft.), included


117x76x117mm (4.6x3x4.6in.)

The manufacturer reserves the right to make changes to the product range and specifications without prior notice.

Care and maintenance  

  • Take the necessary precautions when using the device with children or others who have not read or who do not fully  understand these instructions.
  • Make sure that the air flow channels at the back of the device are not blocked or covered.
  • Do not try to disassemble the device on your own for any reason. For repairs and cleaning of any kind, please contact  your local specialized service center.
  • Protect the device from sudden impact and excessive mechanical force.
  • Store the device in a dry, cool place away from hazardous acids and other chemicals, away from heaters, open fire, and  other sources of high temperatures.
  • Operate the device only in a completely dry environment and do not touch the device with wet or damp body parts.
  • Only use accessories and spare parts for this device that comply with the technical specifications.
  • Check this device and its cables and connections for any possible damage before use.
  • Never attempt to operate a damaged device or a device with damaged electrical parts! Damaged parts must be  replaced immediately by an authorized service agent.
  • If a part of the device or battery is swallowed, seek medical attention immediately.
  • Children should only use the device under adult supervision.

Warranty: lifetime. For further details, please visit our web site:

The original Levenhuk cleaning accessories

original parts

Levenhuk Cleaning Pen LP10

removing dust

Removes dust with a brush
The soft tip is treated with a special cleaning fluid that removes greasy stains
Does not damage optical coatings of the lenses
Leaves no smudges or stains
Levenhuk Inc. (USA): 928 E 124th Ave. Ste D, Tampa, FL 33612,
USA, +1 813 468-3001, [email protected]
Levenhuk Optics s.r.o. (Europe): V Chotejně 700/7, 102 00 Prague 102,
Czech Republic, +420 737-004-919, [email protected]
Levenhuk® is a registered trademark of Levenhuk, Inc.
© 2006—2022 Levenhuk, Inc. All rights reserved.

Documents / Resources

Levenhuk LP90 Wezzer PLUS CO2 Monitor [pdf] User Manual
LP90 Wezzer PLUS CO2 Monitor, LP90, Wezzer PLUS CO2 Monitor, LP90 CO2 Monitor


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