Gastec GOMH-3A Multiple Gas Detector for Oxygen, Flammable Gases, Hydrogen Sulphide

Description

The GOMH-3A combines three high-precision sensing technologies into a single housing:

Oxygen ( $O_2$ ): Uses a galvanic cell sensor (typically the H-3A) for detecting deficiency or enrichment.
Flammable Gases ( $HC$ ): Uses a catalytic combustion sensor (typically the FG-3A) to measure concentrations up to 100% of the Lower Explosive Limit (LEL).
Hydrogen Sulphide ( $H_2S$ ): Uses a controlled potential electrolysis sensor (typically the HS-602E) for high-sensitivity toxic gas detection in ppm.

The device is designed for active sampling, utilizing an internal pump to draw air through an extension hose. This allows users to test the atmosphere of a confined space such as a sewer manhole or a storage tank from a safe distance before entry.

Brand

Gastec

Although, technology is always evolving, one demand on our products never changes: the demand for customer safety. Whenever we contribute to customer safety, we are presented with an opportunity to develop further.

GASTEC holds this corporate creed of safety and development in high esteem, as it strives to grow while always putting customer safety first.

Features

Simultaneous Monitoring: Tracks three distinct gas types in real-time, displaying all readings on a single backlit LCD.
Internal Suction Pump: Enables remote sampling through hoses up to 30m, ensuring pre-entry safety.
Ruggedized Design: Built with impact-resistant materials and a splash-proof housing suitable for harsh industrial sites.
Intelligent Alarm System: Features a loud audible buzzer, high-intensity flashing LEDs, and a vibration motor to alert users even in noisy environments.
Peak Hold Function: Records and displays the highest levels of $H_2S$ and Flammable gas, as well as the lowest level of $O_2$ encountered during the session.

Specifications

Feature	Specification
Model Number	GOMH-3A
Gases Detected	Oxygen, Flammable Gases, Hydrogen Sulphide
Oxygen Range	0.0 – 25.0%
Flammable Range	0 – 100% LEL
$H_2S$ Range	0.0 – 30.0 ppm (Enhanced up to 100 ppm)
Sampling Method	Internal Suction Pump
Dimensions	Approx. 165 x 75 x 45 mm
Weight	Approx. 450g

Applications

Industrial Safety & Confined Space Entry: The GOMH-3A is applied as a critical diagnostic tool before and during work in hazardous zones.

Startup & Self-Check: Turn the unit on in a fresh-air environment. The device will automatically check the battery levels and verify the health of the three internal sensors.
Fresh Air Calibration: Perform the “One-Touch” calibration. This sets the $O_2$ reading to 20.9%, the Flammable gas to 0% LEL, and the $H_2S$ to 0.0 ppm.
Pre-Entry Sampling: Attach an extension hose and probe. Lower the probe into the target area and wait for the pump to draw a sample to the sensors (calculate 1 second per meter of hose plus response time).
Continuous Protection: Once the area is cleared for entry, the worker carries the unit to monitor for “pockets” of gas or leaks that may develop during work.
Sensor Maintenance: Periodically replace the consumable sensing elements:
- Oxygen: H-3A Sensor (Galvanic Cell)
- Flammable: FG-3A Sensor (Catalytic)
- Hydrogen Sulphide: HS-602E Sensor (Electrochemical)