Oxygen Monitor KF25, 0-25% with 10+ Year Sensor

Oxygen Monitor KF25, 0-25% with 10+ Year Sensor

Item #: 99035 (IN-STOCK)


Product Summary

PureAire’s KF25 0-25% Oxygen Deficiency Monitor is ideal for facilities requiring continuous monitoring of gas lines, glove boxes, nitrogen compressors, and vacuum chambers, as well as any locations where low oxygen levels need to be supervised. The unit’s oxygen sensor mounts directly into the process chamber with the use of a KF-type vacuum fitting. The monitor is also well suited for semiconductor tools, OLED manufacturers, and, for any industrial applications where inert gases including, but not limited to, nitrogen, and argon are used. PureAire’s stable, long-life zirconium oxide sensor will last 10+ years in maintained environments without needing to be replaced.

Two-Year Extended Warranty Available for this product in the US, Canada, and Mexico
  • KF25 Flange connector
  • Monitors in Vacuum (20 torr)
  • Long life 10 + year average sensor life
  • Two-Alarm Relays for 19.5% and 18.0%
  • No Scheduled Maintenance Required
  • 3 Year Warranty
  • Digital Display
  • 4-20mA Analog Output (Active)
  • Operates in Freezers at – 40 ºC
  • No Drift due to Thunderstorms or barometric pressure changes
  • Wall mounting brackets and optional plug-in wall power supply
  • UL, C, UL, and CE Approvals
  • 24V DC Power Supply Included (99035)
  • International Power Supply Included (99128)

PureAire’s KF25 Oxygen Monitor is for continuous monitoring of gas lines, 3D printers,  glove boxes, nitrogen gas compressors, vacuum chambers, and locations where low oxygen levels need to be monitored. Unlike electrochemical sensor cells, PureAire’s O2 zirconium sensor cell provides stable oxygen readings even in areas where temperature and humidity levels are changing. PureAire’s KF25 Oxygen Monitor is well suited for monitoring directly in a vacuum.

The heart of the monitoring system is a long-lasting zirconium sensor, which detects low oxygen conditions within seconds and provides accurate measurements over a wide temperature and humidity range. The zirconium O2 sensor cell will operate continuously for 10 or more years and requires an absolute minimum of maintenance. There are no zero or span calibration pots to adjust and when compared to disposable type sensors, our long-life zirconium O2 sensor can save up to $475 annually and will pay for itself in just over 3 years!

The Monitor’s unique sensor mounts directly into chambers or load locks through the use of a KF-type vacuum fitting. Monitoring oxygen directly under a vacuum eliminates the need to change the environment back to ambient and can improve thru put. The  Monitor also provides stable readings even in areas that contain high electromagnetic fields.

Sampling Method Diffusion
(Supplied with KF 25 Vacuum Fitting)
Gases Detected Oxygen (O2)
Range 0 – 25 % O2
Accuracy Delivers ±0.2% O2 accuracy (± 1 % of full range)
Operating Temperature -40° to 140°F (-40° to 60 ºC)
Display 3/4″ LCD Digital Display, Back Lit, 3 Alarms LED´s
Sensor Type Long-life zirconium oxide sensor cell
Sensor Life 10+ years under Normal Conditions
Signal Outputs 4-20 mA Analog Output (Active)
Dual-Level Alarm Relay Contacts
Power Requirements 24 VDC
250 mA
Width 5.0 in
127 mm
Height 5.5 in
140 mm
Depth 3.25 in
83 mm
Weight  2 lb
0.9 kg
Enclosure Polycarbonate
Calibration Calibration is not required. Periodic span adjustment as needed.
Country of Origin USA
Harmonized Tariff Code 8531.10.0045
Additional O2 Monitor Accessories List Price
8 Channel Controller $3,355.00 US (P/N # 99196)
Horn and Strobe  $190.00 US (P/N # 42002)
Remote Display $435.00 US (P/N # 99091)

Connects to DCS and PLC Controls
The AirCheck O2 Deficiency Monitor is 24 V DC powered and transmits continuous oxygen concentration levels to any distributive control system or programmable logic controller.

PureAire’s Oxygen Sensor Cell
The AirCheck O2 Deficiency Monitor uses an exclusive Current Limiting Zirconium Oxide Oxygen sensor that never requires a reference gas. Unlike concentration-type zirconium cells that must have a reference gas, PureAire’s O2 monitor can operate in 100 % nitrogen environments. Capable of detecting 0 % up to 95 % oxygen levels, the current limiting O2 sensor operates at a lower temperature than competitive concentration type cells. The average life of PureAire’s O2 sensor is over 8 years in most environments. The AirCheck O2 Deficiency Monitor never needs calibration. A simple, periodic span adjustment may be necessary. The earth is a wonderful source of calibrated oxygen and under ambient levels; PureAire’s O2 monitor is continuously being challenged to 20.9 %.  The only optional response test required is to subject the O2 system to nitrogen periodically.

O2 Monitor System Features
The AirCheck O2 Deficiency Monitor is available in many different configurations perfect for OEM process tool installation. PureAire uses a sophisticated built-in CPU that is flexible to provide users with a low-cost basic display-only monitor or a full-featured monitor with dual-level, user-selectable alarm relays.

Oxygen Monitor KF25, 0- 25% Literature

O2 Deficiency/Diffusion Monitor – Manual – Rev 5.01 (Post Summer 2023)

Safety Risks of Oxygen Deficiency

NIH – Protocol for Use & Maintenance of Oxygen Monitoring Devices 2021

Comparison O2 Zirconium Oxide vs EC cell

Comparison of 10-Year Sensor vs Disposable (Electrochemical)

O2 Test Against other Companies

Oxygen Monitor Sales Presentation

Remote Digital Display p/n 99091

Horn/strobe 24VDC Red

horn and strobe


8-Channel Programmable Controller for Oxygen, Carbon Dioxide, or Toxic/Combustible Gas Monitors