Belimo Gas Monitors for a Wide Range of Applications

Gas monitoring is not a one-application problem, but every application shares the same goal: protecting occupants. Enclosed parking facilities must control vehicle emissions. Boiler rooms, commercial kitchens, and battery charging areas rely on gas monitoring to detect toxic or combustible gas leaks. Supermarkets, cold storage warehouses, and refrigerant machinery rooms need early refrigerant leak detection and coordinated alarming. Belimo addresses these needs with a configurable range of gas monitors for commercial and light industrial applications.

Monitoring, Alarming, and Ventilation Control

Belimo 22G Series gas monitors are factory calibrated and can monitor up to 2 gases simultaneously. Standard features include 3 adjustable alarm levels, an internal horn and strobe alarm, an LCD, a 4-button keypad, and optional password protection.

CAN bus communication supports standalone operation and daisy-chain networks of up to 32 devices. Devices on the same network can be assigned to programmable groups for multiple ventilation zones. Depending on the gas monitor or communication module used, the system can support BACnet MS/TP for BMS integration, provide configurable analog outputs and relays to control fans, dampers, alarms, and other equipment, and receive an external signal through a binary input, such as one from a manual ventilation switch.

Available sensing technologies, signal configurations, housing ratings, enclosure options, and other accessories vary by gas and application.

Vehicle Emissions

Belimo vehicle-emissions monitors support demand-controlled ventilation in enclosed parking garages, ambulance bays, fire stations, loading docks, automotive and truck maintenance facilities, boiler rooms, and similar spaces where combustion equipment or vehicles may operate.

The vehicle-emissions range includes the 22G02 for carbon monoxide (CO) from 0 to 250 ppm, the 22G14 for nitrogen dioxide (NO2) from 0 to 10 ppm, and the 22G0214 for simultaneous CO and NO2 monitoring in one device.

Monitoring actual gas concentrations allows the ventilation system to operate in response to conditions instead of relying only on continuous or scheduled fan operation. This can reduce unnecessary fan energy and the loss of heated or cooled air while supporting safe indoor conditions.

The 22G02, 22G14, and 22G0214 model families are fully listed to UL 2075 and ULC-588. The certification applies to the complete devices, including the monitor, sensing element, electronics, enclosure, alarm functions, and end-of-life supervision.

Indoor Air Quality

The 22G15 carbon dioxide (CO₂) monitor family is available in three measurement ranges: 0 to 2,000 ppm, 0 to 5,000 ppm, and 0 to 10,000 ppm.

The 2,000 ppm range supports occupied-space applications such as classrooms, conference rooms, and warehouses. The 5,000 and 10,000 ppm ranges support continuously occupied spaces, as well as breweries, compressor rooms, greenhouses, indoor growing facilities, mechanical rooms, and medical gas storage areas.

Combustible and Toxic Gases

Belimo offers monitors for a range of combustible, toxic, and oxygen-related hazards. They can be configured with 1 or 2 sensor modules. Applications include cold storage and compressor rooms, boiler rooms, commercial kitchens, lead-acid battery charging stations, laboratories, swimming-pool mechanical rooms, medical gas storage.

• 22G04 ammonia (NH3): 0 to 250 ppm
• 22G05 methane or natural gas (CH4): 0 to 50% LEL
• 22G06 propane (C3H8): 0 to 50% LEL
• 22G08 hydrogen (H2): 0 to 50% LEL
• 22G16 hydrogen sulfide (H2S): 0 to 50 ppm
• 22G17 chlorine (CL2): 0 to 10 ppm
• 22G22 oxygen leak: 0 to 50% O2
• 22G23 oxygen depletion: 0 to 50% O2 for argon, helium, or nitrogen applications

Methane, propane, and hydrogen use catalytic sensors, which detect combustible gases through a reaction on a heated sensing element. Belimo does not advise installing 2 catalytic sensor modules in the same monitor because of excessive power draw. In dual-gas configurations, the two gases may need to be monitored at different heights because of differences in gas density. In these cases, the optional A-22G-A14 remote enclosure allows 1 sensor module to be installed separately from the main monitor.

Refrigerant Gas Leak Detection

The 22G21-5C broadband infrared refrigerant monitor measures from 0 to 2,000 ppm and monitors 1 user-selected refrigerant at a time. Unlike the gas-specific sensor modules used elsewhere in the 22G Series, the 22G21-5C uses a single broadband infrared sensing element. Technicians select the refrigerant to be monitored directly on the device, allowing the same monitor to be configured for any of 21 refrigerants. The available refrigerants are R11, R22, R23, R32, R125, R134a, R404A, R407A, R407C, R407F, R410A, R448A, R449A, R452A, R454B, R455A, R507, R513A, R1233zd, R1234yf, and R1234ze.

The broadband approach simplifies commissioning and service. Technicians can calibrate the monitor using R134a and then configure it to measure another refrigerant from the selection list. This reduces the need to carry a separate calibration-gas bottle for every refrigerant used across different sites.

The 22G21-5C communicates through CAN bus. For machinery rooms and similar applications, it can be combined with C-22G-5A or C-22G-5B communication modules for BACnet MS/TP and additional outputs, a C-22G-50 4-relay unit for equipment control, and an EXT-AS-HS-BLU (blue), EXT-AS-HS-AMB (amber), or EXT-AS-HS-CLR (clear) external audible and visual alarm. The C-22G-5B communication module can serve as a remote display in a refrigerant monitoring system. Together, these components support system designs intended to meet applicable ASHRAE 15 and CSA B52 requirements.

Selecting the Right Signal Configuration

The final letter in a 22G series gas monitor model number identifies the signal configuration:

• A models: CAN bus, BACnet MS/TP, 1 binary input, 1 relay, and 2 configurable analog outputs
• B models: CAN bus, BACnet MS/TP, 1 binary input, and 2 relays
• C models: CAN bus

The exact configurations available vary by gas and model. As outlined above, the refrigerant monitor is a C model and uses separate communication or relay modules when BACnet MS/TP, analog outputs, or relay outputs are required.

Installation, Maintenance, and Accessories

Sensor placement depends on the target gas, its density relative to air, the potential leak source, coverage area, obstructions, and applicable code requirements. Belimo gas monitors are intended for stationary commercial and light-industrial applications in non-hazardous locations. Installation, operation, and maintenance must follow the operating manual and all applicable laws and regulations.

Belimo gas monitors require calibration at least once per year, or more frequently when specified by the application. Their sensor modules are field replaceable, allowing a sensor module to be replaced without replacing the entire gas monitor. The A-22G-A22 calibration kit and A-22G-A23 replacement cap and hose are used for vehicle-emissions, indoor-air-quality, combustible, toxic, and oxygen monitors. The 22G21-5C broadband refrigerant monitor uses the dedicated A-22G-A08 refrigerant calibration kit and A-22G-A09 replacement calibration cap and hose.

Additional accessories include the A-22G-A12 splash-proof enclosure, A-22G-A13 duct-mount enclosure, A-22G-A14 remote enclosure for mounting 1 sensor separately, A-22G-A24 security screws, A-22G-A50 50 VA transformer, A-22G-A100 100 VA transformer, EXT-AS-HS-BLU (blue), EXT-AS-HS-AMB (amber), and EXT-AS-HS-CLR (clear) external horn and strobe alarms, C-22G-5A and C-22G-5B communication modules, and C-22G-50 4-relay unit.

Belimo gas-monitoring products carry a 5-year warranty, while sensor modules carry a 1-year warranty.

A Flexible Approach to Gas Monitoring

From parking garages and occupied spaces to mechanical rooms, laboratories, light-industrial facilities, and refrigeration systems, Belimo gas monitors support measurement, alarming, ventilation control, and system integration. The range can scale from 1 local monitor to a networked, multi-zone gas-monitoring system while maintaining a consistent approach to setup, operation, and service.

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