Gas Sensor Monitor


Bacharach’s all new GDC-350 full-featured fixed gas monitors provide superior operation - standalone or as part of
a larger system utilizing the standard analog outputs. This state-of-the-art instrument can detect a wide range of
gases including carbon monoxide (CO), oxygen (O2), combustible gases, refrigerants and total volatile organic
compounds (TVOCs). The GDC-350 provides a unique two sensor interface, allowing for multiple gases to be
detected with onboard or remote sensors. Sensors can be located integral to the unit or remotely allowing for
sensors to be placed directly in areas where potential leaks can occur. Bacharach’s proprietary calibration
algorithms extend the amount of time required between calibrations, reducing maintenance costs and lowering the
overall cost of ownership for non-critical applications.

The GDC-350 has all the features and functionality for any application. LED alarm indicators visually indicate when alarm conditions are met and an audible alarm alerts nearby personnel. An onboard alpha numeric display shows gas readings in real time for each sensor. Integral dry contact relays are available to drive external audible / visual alarms, activate fans, or connect to building management and control systems. Installation and maintenance is simple and easy, reducing overall system cost. A pre-wired plug-in option is available for out-of-the-box operation. Simply plug the unit into any standard AC outlet for immediate detection and protection.


Gases Detected:Carbon Monoxide (CO), Oxygen (O2), Nitrogen Dioxide (NO22), Nitric Oxide (NO), Sulfur Dioxide (SO2), Combustible Gases and Refrigerants
 COO2NO2NOSO3Combustible GasRefrigerants
0-200 ppm
1 ppm
0-25% Vol.
0.1% Vol.
0-10 ppm
0.1 ppm
0-100 ppm
0.1 ppm
0-20 ppm
1 ppm
0-2000 ppm
1 ppm
Detection Principle:
Electrochemical, Solid State
-5° F to 120° F (-20° C to 50° C)
Relative Humidity:
15-90% RH Non-Condensing
Housing Options:

Standard: Rugged PVC
NEMA 4X: Watertight polycarbonate

Alarm Indicators
LED indicators for Power, Fail, Low Gas Alarm, High Gas Alarm
80 dB Audible alarm w/ silence
Alarm Relay:
Two S.P.D.T. dry contact relays, 5 amps @ 250 VAC
Standard: 5.3” L x 6.8” W x 2.6” D (135 mm x 173 mm x 66 mm) 
NEMA 4X: 5.1” L x 7.1” W x 3.9” D (130 mm x 180 mm x 100 mm)
Standard: 1 lb (0.45 kg) NEMA 4X: 1 lb (0.45 kg)
Outputs: Linear 4-20 mA (dual outputs for 2 sensor onboard configurations
VDC 3 conductor shielded; VAC 4-conductor shielded; optional pre-wired power supply 110-220 VAC
Automatic resetting thermal
12-28 VAC or 15-30 VDC; 150 mA
CSA Certified; UL Certified; C-Tick Certified

GDC-350 Part Number Configurator 59AB-CDEF

 StandardStandardProduct OptionEnclosure OptionSensor OptionSensor Sensor
 59ABC and DE and F
   0=N/A0=N/A00=No onboard sensor00=No onboard sensor (or remote GDC-150 as an input)
   1 = Single sensor, onboard1 = Standard enclosure, no display01 = CO01 = CO
   2 = Single sensor, remote2 = Standard enclosure, w/ display03 =O203 = O2
   3 = Dual sensor, onboard3 = NEMA 4X enclosure, no display04 = NO204 = NO2
   4 = Dual sensor, onboard & remote4 = NEMA 4X enclosure, w/ display06 = NO06 = NO
    5 = NEMA 4X enclosure, w/ splash guard, no display09 = SO209 = SO2
    6 = NEMA 4X enclosure, w/ splash guard & display 30 = Combustible Gas
    7 = Standard enclosure, no display, pre-wired supply 31 = Refrigerants (must be remote)
    8 = Standard enclosure, w/ display, pre-wired supply 32 = TVOCs (must be remote)

GDC-350 Common Configurations

Part NumberDescription
5911-0100GDC-350 Standard, CO, single sensor (onboard), no display
5911-0400GDC-350 Standard, NO2, single sensor (onboard), no display
5914-0600GDC-350 NEMA 4X, NO, single sensor (onboard), w/ display
5914-0900GDC-350 NEMA 4X, SO2, single sensor (onboard), w/ display
5918-0100GDC-350 Standard, CO, single sensor (onboard), w/ display and pre-wired power supply
5922-0030GDC-350 Standard, Combustible Gas, single sensor (remote), w/ display
5927-0031GDC-350 Standard, Refrigerant sensor, single sensor (remote), no display, pre-wired power supply
5933-0104GDC-350 NEMA 4X, CO & NO2, dual sensors (onboard), no display
5944-0130GDC-350 NEMA 4X, CO & LEL, dual sensor (onboard & remote), w/ display
5944-0330GDC-350 NEMA 4X, O2 & Refrigerant, dual sensor (onboard & remote),
w/ display

GDC-350 Accessories

Part NumberDescription
5209-0004Splash guard (NEMA 4X only)
5209-0006Calibration adapter for all other sensors
5909-0003Guard to protect GDC-350 (16 gauge galvanized metal)
5909-0004Enclosed external transformer (120 VAC to 22 VAC)