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Edmondson Supply will be closed May 24th 2024. Final guaranteed shipping time is 12pm EST Thursday, May 23rd. Regular shipping will resume Tuesday, May 28th.
Edmondson Supply Will Be Closed May 24th 2024. Final guaranteed shipping time is 12pm EST Thursday, May 23rd. Regular shipping will resume Tuesday, May 28th.

Fieldpiece SOX3 Combustion Checker with Auto Pump

Save 15%
Original price $555.00
Current price $471.75
Currently 1 in stock.

Fieldpiece SOX3 Combustion Checker with Auto Pump

Products usually ship within 1 business day.

Tune Up the Furnace

  • Measures flue temp and %O2
  • Calculates %CO2, %EA, and combustion efficiency
  • Hands-free testing with magnet, R-cone, and automatic pump
  • Programmable for custom fuel types

The SOX3 Combustion Check is a great tool to easily tune furnaces when a full combustion analysis isn't necessary. Designed specifically for HVACR pros, the SOX3 provides all the essential measurements needed to tune most combustion equipment. It directly measures %O2 and flue temperature, and calculates %CO2, %Excess Air, and combustion efficiency.

Like all Fieldpiece products, the SOX3 Combustion Check Tool was designed to help HVACR professionals do more with their tools. From custom fuels to field-replaceable oxygen sensors, the SOX3 can be trusted to measure up for any furnace tuning job.

  • Automatic Electric Pump with Pause - Pump works automatically so there's no hand pumping, and techs can pause the pump at any time to save battery life
  • Field-replaceable Oxygen Sensor - The SOX3 Oxygen Sensor indicators tells techs when a new sensor is needed. With calibration data stored on the sensor, it can be swapped out in seconds, so there's never a need to send your instrument in for calibration.
  • Hands-free Testing - The threaded R-cone holds the barrel firmly in the flue, and the strong magnet on the back of the SOX3 holds the instrument firmly to the side of the flue, while the internal electric pump does all the work. Techs simply view the results on the triple line display.
  • Combustion Efficiency - Quickly calculated and displayed on the screen, the SOX3's combustion efficiency calculation is great measurement to help determine the health of a furnace.
  • Custom Fuels - Not only does the SOX3 test Natural Gas, Oil #2, and Propane, but it can be quickly, and easily programmed to test any type of fuel. So non-conventional furnaces are just as easy to tune and conventional furnaces.


  • Sensor Type:  Highly accurate oxygen sensor
  • Operating environment:  32 to 122°F (0 to 50°C) at <75% R.H.
  • Storage environment:  -4 to 140°F (-20 to 60°C) at  <80% R.H. with battery removed from meter
  • Temperature Coefficient:  0.1 times the applicable accuracy per ° from 32°F to 64°F and 82°F to 122°F (0 to 18°C and 28 to 50°C)
  • Battery:  9V
  • Battery Life:  28 hours typical alkaline
  • Auto Power off:  After 15 minutes
  • Accuracy:  Stated accuracy at 23°C±5°C, <75% R.H.
  • Dimensions:  45.0mm(H) x 69.8mm(W) x 211.7mm(D)
  • Weight:  approx. 579.7g with battery
  • Display:  4 digit liquid crystal display(LCD) with maximum reading of 9999

What's Included:

  • Combustion Check  - SOX3
  • Barrel and Thermocouple Handle - RSOX3
  • Threaded Barrel Lock - RCONE2
  • Filter accessory kit - RAOX9
  • Padded, Blow-molded Case


User Manual