1231 & 1232 In-Situ Oxygen Probes

In-situ Oxygen Analysis for Concentrations as low as 1 × 10-30% to 100%

Specifications Data Sheet

The Novatech 1231 and 1232 Oxygen probes incorporate the world’s most rugged zirconia sensors. They are ideal for:

  • Flue gas analysis
  • Oxygen levels in boilers, kilns and furnaces
  • Combustibles analysis
  • Carbon potential measurement
  • Water vapour concentration and dew point measurement
  • Inert and sterile packaging
  • General industrial use
  • Annealing furnaces

The Novatech 1231 and 1232 Oxygen Probes are Australian-made and embody the research and development of one of Australia’s premier research organisations, the CSIRO. The Novatech 1231 and 1232 probes are highly accurate, and have minimal drift (±1%). The Novatech in-situ probes are highly durable; choose the Novatech 1231 for analysing gases with temperatures below 900ºC (1650ºF) and the Novatech 1232 for temperatures ranging between 700°C and 1400°C (1290ºF to 2550ºF).

The Novatech 1231 and 1232 probes have a very rapid response to changes in Oxygen levels

With a response time of less than 4 seconds, potentially hazardous situations such as those caused through the build-up of dangerous fuel-rich conditions can be avoided.

The Novatech 1231 and 1232 probes are easy to install

The probes are inserted into the flue, or other measuring point, and the threaded nipple (1231 has 1.5“ BSPT/NPT; 1232 has 3/4” BSPT/NPT) is screwed on to a mating socket welded to the process.

Connect the probe cable to the transmitter, and you are ready to measure and/or control the combustion process.

Novatech offers you safety of operation

The Novatech 1732 Oxygen Transmitter provides a main burner safety interlock. This is the ONLY reliable way of preventing potentially explosive situations.

Should the main burner fail or shut down then the sensor’s heater is de-energised so that dangerous flue gases cannot be ignited by the probe.


Model 1231 1232
Applications Combustion Flue gasses below 900°C (1650°F)
(see note 1)
Combustion flue gasses above 700°C (1290°F) with no contaminants; eg natural gas, light oils
Temperature Range

0°C to 900°C
(32°F to 1650°F)

700°C to 1100°C 253MA Stainless Steel
(1290°F to 2010°F)
700°C to 1400°C Alumina Ceramic
(1290°F to 2550°F)

Probe Insertion Length Standard Lengths:
250, 350, 500, 750, 1000, 1500mm
(see note 3)
Standard Lengths:
500, 750, 1000mm
Process Connection 1.5" BSPT or NPT 3/4" BSPT or NPT
Outer Sheath 32mm OD 316 Stainless Steel, 42mm with optional filter 19mm OD 253MA Stainless Steel or Alumina Ceramic
Electrical Connection Weather-proof plug-in connector or optional screw terminals.
The plug connector can be supplied with the cable.
Cable 1231 Cable can be supplied with a separate polyurethane reference airline. 1232 Cable has an integral airline.
Heater Yes No
Internal Thermocouple Type 'K' Typically Type 'R'.
Also available with no TC, Type 'S' or 'K'
(see note 2)
Response Time Typically <4 seconds Typically <1 second
Head Temperature -25°C to 100°C ( -15°F to 210°F) with weatherproof connector
-25°C to 150°C ( -15°F to 300°F) with optional screw terminals
-25°C to 150°C ( -15°F to 300°F)
Reference Gas Air 50 cc/minute approx. Pump can be supplied within transmitter
Calibration Check Gas Flow Approx. 2 litres/minute
Ref. Air Connection 1/4" tube Integral air line through connector or 1/4” tube
Particulate Filter Optional sintered titanium alloy
30 µm standard, 15µm extra fine
Not available
Cal. Check Gas Connection 1/8" NPT female
Weight approx. 2Kg + 165g per 100mm insertion length
(see note 4)
approx. 1Kg + 100g per 100mm insertion length

For information regarding the 1231HWV probe refer to the 1735 Water Vapour Transmitter


  1. Care must be taken to avoid contact with explosive or inflammable gases with 1231 heated Oxygen probes when hot. Novatech Oxygen transmitters have built-in safety protection which disconnects the heater when the main flame is off.
  2. A flue gas thermocouple is required with a 1232 probe if a flue gas temperature display on the transmitter is required. A 1231 Oxygen probe has an integral type K thermocouple which is used to control the sensor temperature.
  3. If your process requires a specific length probe not listed in the table above, contact Novatech to discuss non-standard lengths.
  4. The precise weight of a probe will vary slightly depending on the configuration of head connectors and filters.

Ordering Information

Probes are made to order based on the following information;

  • Probe Type - 1231 or 1232
  • Probe insertion length. Available lengths are displayed in the table above
  • Weather-proof plug or screw terminal connections
  • No filter / Sintered 30µm or 15µm titanium alloy filter (1231 only)
  • Process connection thread type NPT by request
  • Non standard thermocouple type (1232 only)
  • Cable supplied with plug connector or no connector