Maintenance-free hydrogen area monitor for battery rooms, with a hydrogen-specific solid-state sensor
A battery room needs a hydrogen-specific detector that alarms well below the lower flammability limit, drives the ventilation through a relay and needs no periodic calibration. The HY-GUARD monitor measures H2 from 0.4 to 5 % by volume with ±0.3 %, switches its relays at 1 % — 25 % of the lower flammability limit — and at 2 %, signals faults through a third relay and communicates over Modbus RTU and 4-20 mA, with continuous self-calibration and a maintenance-free service life of more than 10 years.
HY-GUARD key data
- Measuring principle: hydrogen-specific solid-state sensor with no cross-sensitivity to other gases, so the HY-GUARD avoids the false alarms and drift of catalytic-bead and metal-oxide sensors; two non-consumable sensors alternate, and while one measures the other corrects its drift every 12 hours.
- Range and accuracy: 0.4-5 % H2 by volume, with a 0.4 % lower detection limit and ±0.3 % H2 absolute accuracy (±1 % above 2 %); prolonged exposure above 5 % may damage the sensor.
- Alarms and relays: three changeover relays rated 12 A at 125 VAC or 28 VDC for the 1 % H2 low alarm, the 2 % high alarm and fault; the fault relay stays energised in normal operation and de-energises on a fault. Local indication through LEDs and an 85 dB buzzer.
- Communications: Modbus RTU over two-wire RS-485 (19,200 baud default, address 1-247) and a 4-20 mA output linear from 0 to 5 % H2, with 2 mA during warm-up and 3 mA on error; model 8111 combines all outputs and models 8110, 8101 and 8100 are variants with fewer outputs.
- Power and start-up: AC or 15-60 VDC with automatic switchover and 10 W maximum; once powered, the HY-GUARD warms up for up to 6 minutes before entering normal monitoring.
- Installation: at the highest point of the room, cabinet or enclosure, because hydrogen rises; direct punch-out mounting, on a 4-11/16" junction box or, with the adapter plate, on 35 mm DIN rail, a flat surface or a magnetic mount; 132.5 × 130.5 × 52.9 mm and 0.5 kg.
- Environment: rated 15 to 40 °C and operational −25 to 50 °C, 0-95 % RH non-condensing, 0.8-1.2 atm and up to 2,000 m altitude, indoors.
- Standards and certifications: IEC 61010-1, CE, FCC Part 15, REACH and RoHS; the HY-GUARD helps meet IFC, NFPA 1, NFPA 2, NFPA 855, OSHA 1910, IEC 62485-2, IEC 62933-5-2 and IEEE 484 & 1635.
Advantages
Hydrogen safety without maintenance
A hydrogen-specific sensor with continuous internal self-testing verifies its own health and accuracy over its whole life, with no manual calibration and no board replacements.
No false alarms
The sensor has no cross sensitivity to other gases, eliminating the drift, false triggers and premature failures typical of catalytic-bead and metal-oxide sensors.
Compliance built in
It keeps installations aligned with global fire and safety standards — IFC, NFPA 1, NFPA 2, NFPA 855, OSHA 1910, IEC 62485-2, IEC 62933-5-2 and IEEE 484 & 1635.
Measured and reliable
It measures H2 from 0.4 to 5 % with ±0.3 % accuracy and a 50-70 second response, providing 1 % and 2 % concentration alarms and a fault indicator.
Flexible integration
Modbus RTU (RS-485), 4-20 mA analog output and dry relay contacts, with wall, DIN-rail, junction-box and magnetic mounting and AC/DC power with automatic switchover.
Applications
- Standby-power and emergency battery rooms.
- Lead-acid and NiCad battery installations and cabinets.
- Telecommunications backup and data-centre standby power.
- Electrical substations, switchgear and SCADA systems.
- Hydrogen generation, forklift charging and fuel-cell applications.
About the product
The monitor runs on 85-264 V AC and 15-60 V DC with automatic switchover and a service life above 10 years; four models cover the communication needs of each installation — 8111 (Modbus RTU, 4-20 mA, dry contacts and fault indicator), 8110 (4-20 mA and dry contacts), 8101 (Modbus RTU and dry contacts) and 8100 (dry contacts with 1 % and 2 % alarms).
Technical specifications
| Detection range | 0.4-5 % H2; lower detection limit 0.4 % |
| Accuracy | ±0.3 % H2 (±1 % above 2 %) |
| Response time | 50 to 70 seconds |
| Alarms | 1 % and 2 % H2 concentration; fault indicator |
| Communication | Modbus RTU (RS-485); 4-20 mA analog; dry relay contacts |
| Power | 85-264 V AC; 15-60 V DC; automatic AC/DC switchover; 10 W max |
| Mounting | Wall, DIN-rail, junction box and magnetic |
| Service life | Above 10 years; maintenance-free, no calibration |
| Environment | 15 to 40 °C; 0-95 % RH non-condensing |
| Dimensions and weight | 132.5 × 130.5 × 52.9 mm; 0.5 kg |
| Models | 8111, 8110, 8101 and 8100 (communication variants) |
| Relays | 3 changeover (1 %, 2 % and fault); 12 A at 125 VAC / 28 VDC; fault relay energised in normal operation |
| Analog output | 4-20 mA = 0-5 % H2; 2 mA during warm-up, 3 mA on error |
| Certifications | IEC 61010-1, CE, FCC Part 15, REACH and RoHS |
Frequently asked questions
Which hydrogen detector is best for a battery room?
One that is hydrogen-specific, does not react to other gases, watches the 1 % H2-in-air threshold — 25 % of the lower flammability limit set by the codes — and starts the exhaust through a relay. The HY-GUARD measures 0.4 to 5 % with ±0.3 %, switches relays at 1 % and 2 %, has a fault relay that de-energises on any abnormality and needs no calibration for more than 10 years.
Where should it be placed in the battery room?
At the highest point of the room, cabinet or enclosure, because hydrogen is much lighter than air and collects at the top; the HY-GUARD is for indoor use. It mounts directly through the punch-out, on a 4-11/16" junction box or, with the adapter plate, on 35 mm DIN rail, a flat surface or a magnetic mount, and several units can share the RS-485 bus, with the terminating resistor enabled on the last one.
What does it detect?
Hydrogen (H2) from 0.4 to 5 % by volume, with a lower detection limit of 0.4 % and ±0.3 % accuracy.
Does it need calibration?
No. It is maintenance-free, with continuous automated self-calibration and no board replacements over a 10-year-plus service life.
Which standards does it help meet?
IFC, NFPA 1, NFPA 2, NFPA 855, OSHA 1910, IEC 62485-2, IEC 62933-5-2 and IEEE 484 & 1635, among others.
How does it communicate?
Through Modbus RTU (RS-485), a 4-20 mA analog output and dry potential-free relay contacts, with 1 % and 2 % alarms.
How is it mounted and powered?
Wall, DIN-rail, junction-box or magnetic mounting, with 85-264 V AC and 15-60 V DC power and automatic switchover.
