skip to Main Content
        (800) 368-5719 email customer service

721 Combustible Gas Leak Detector

The 721 offers 10ppm sensitivity to detect combustible gasses.

Easily operated with one hand, leaks are pinpointed using the audio and visual indicators. An adjustable “tic” rate helps eliminate background gas concentration in contaminated environments.

  • Combustible Gas Leak Detector capable of displaying real ppm, stepped ppm, and %LEL (Lower Explosive Limit)
  • 10ppm sensitivity (methane)
  • Detect combustible gases including natural gas, propane, butane, etc.
  • Thumbwheel adjustable tic rate to locate leaks quickly and accurately
  • Two line display with bargraph and backlight
  • Audio / Visual alarm indication with user adjustable alarm point
  • Earphone jack for use in noisy environments
  • Approximately 20 hours of continuous use (C cell alkaline batteries x2)

Product Documentationpdf-icon1

Click below to view or download product documentation PDFs:

721 Manual

721 Data Sheet

$295.00 USA Suggested List Price

Where to Buy TPI Products

Model 721 Combustible Gas Leak Detector

The ergonomically designed 721 is a hand-held, combustible gas leak detector. It is capable of finding combustible gas leaks in pipes, fittings, regulators, etc. Additional features include the capability to display %LEL, leak level in ppm, and user adjustable alarm point.

Perform the following tests and/or measurements with the 721 leak detector:

  • Locate combustible gas leaks in joints and fittings
  • Determine Lower Explosive Limit percentage
  • Determine the combustible gas leak level in ppm (parts per million)

Gases Detected: (partial listing): Acetone, Acetylene, Alcohol, Ammonia, Benzene, Butane, Ethanol, Ethylene Oxide, Gasoline, Hexane, Hydrogen, Methane, Naphtha, Natural Gas, Paint Thinners, Propane, Solvents

Standard accessories:
• Carrying Pouch (A780)
• Instruction Manual
• Battery and Sensor (Installed and Calibrated)

 Model 721 Specifications
 Combustible Gasses Detected
 (Partial List)
 Acetone, Acetylene, Alcohol, Ammonia, Benzene, Butane,
 Ethanol, Ethylene Oxide, Gasoline, Hexane, Hydrogen, Methane,
 Naphtha, Natural Gas, Paint Thinners, Propane, Solvents
 
 Leak Detection Sensitivity  10ppm (methane)
 Accuracy  +/-10%
 Sensor Type  Low power semiconductor
 Probe Length  16”
 Leak Indication  Audio / Visual
 Adjustable Tic Rate  Yes
 Alarm  Audible / Visual (User settable)
 Display type  Dual display with backlight
 Leak Level Read Out  Yes, 0 to 9999ppm
 %LEL Indication  Yes, 0% to 19.9%
 Stepped ppm read out  Yes, 0, 500, 1000, 3000, 5000, 9999ppm
 Internal Sample Pump  No
 Intrinsic Safety Rated  No
 Battery  “C” cell (2)
 Weight  1.1 lb

Model 721 Applications

  • Detect combustible gasses including natural gas methane, propane (LPG), gasoline, diesel, and kerosene
  • Trace natural gas lines and fittings for leaks
  • Check gas generation for leaks

Frequently Asked Questions

1. What is the difference between the HXG-2 and the 720b?
The HXG-2 is intrinsically safe and has an adjustable alarm.

2. Can I use the 720b or HXG-2 to test for carbon monoxide as well as combustible gas leaks?
The HXG-2 and 720b are designed to detect combustible gas leaks. The 735 or 775 are the best choices to test for carbon monoxide as well as combustible gas leaks.

3. What is the difference between the 735 and 775?
Both the 775 and 735 can be used to test for carbon monoxide in ambient air as well as test for combustible gas leaks. The 735 is pump driven and can be used to test for CO infurnaces as well. When testing for combustible leaks the 775 uses an audible “tic” and visual indication while the 735 has audible indicationand displays the leak level in %LEL.

4. I only need to test for combustible gas leaks, which detector should I choose?
The 725 is pocket sized with LED and audible indicators that activate at preset leak levels. The 725 can detect a leak but does nothave the capability to determine the source. The 720b and HXG-2 are more sensitive, utilize a thumb wheel adjustable “tic” rate, and have goosenecks that enable them to reach into tight areas and not only detect a leak but determine the source. The HXG-2 has an adjustable alarm and is intrinsically safe.

5. I need to be able to produce a “hardcopy” of test results. Do any of the TPI detectors have this capability?
Yes, the 735 has an infrared interface for printing testing results.

6. What gases can be detected?
Gases that can be detected include but are not limited to Acetone, Alcohol, Butane, Gasoline,Kerosene, Methane, Natural Gas, and Propane.

TPI Model 721 Demonstration Video

Back To Top