Gas Alarm GX-D500

The professional CO₂ detector for beverage dispensing systems, breweries and cold rooms: permanently installed, standards-compliant warning, with relay to shut off the hazard source

The Schabus Profi CO₂ Detector GX-D500 is a CO₂ warning device for technical installations where carbon dioxide can be released from pressurized cylinders or pipelines. It monitors rooms with beverage dispensing systems, small and medium-sized breweries, wine and fermentation cellars, cold rooms as well as areas with dry ice processing and storage. An external NDIR infrared sensor measures the CO₂ concentration, and an illuminated plain-text display continuously shows the current value in %. In the event of danger, the GX-D500 warns optically and acoustically.

The alarm thresholds are fixed and comply with DIN 6653-2:2015-06: a pre-alarm at 1.5 % CO₂ (15,000 ppm) and a main alarm at 3.0 % CO₂ (30,000 ppm). They are deliberately set for technical defects and leaks, such as a porous hose, a defective valve or a leaking container. Exhaled air from people does not trigger an alarm. In the event of an alarm, a potential-free relay switches, which can, for example, activate forced ventilation or close a solenoid shut-off valve. A second relay reports faults to the building management system.

The GX-D500 is a surface-mounted device for permanent wall installation. The sensor is mounted at the location where the CO₂ is to be detected, preferably close to the floor. It is already pre-assembled; the device comes with mounting material and tools and is ready for immediate installation by a qualified specialist.

Measure, warn, shut off

The GX-D500 combines an external NDIR sensor with two standards-compliant alarm levels, a display with comprehensive status indication and two potential-free relays.

What’s in the box

The device comes with a pre-assembled sensor and all mounting material. It has no options and no additional variants.

• CO₂ warning device GX-D500 with pre-assembled external sensor
• Operating and installation instructions
• Mounting material: screws and wall plugs for wall mounting
• PG cable glands: 2 large and 1 small
• 2 screwdrivers

The cables for mains connection and relay outputs are installed on site by the specialist. The connecting cables leading to the gas detector must be permanently installed as surface-mounted cables.

How the GX-D500 is constructed

The device consists of a control unit in a surface-mounted housing and an external sensor. The sensor measures the CO₂ concentration; the control unit evaluates the signal, displays it, triggers the alarm if necessary and switches the relays.

Two levels, two signals

Depending on the CO₂ concentration, the GX-D500 warns in two stages. The thresholds comply with DIN 6653-2:2015-06 and can only be adjusted at the factory.

In the main alarm you can mute the signal tone with the RESET button until the CO₂ concentration decreases and the system returns to the pre-alarm.

Using the relays correctly

The potential-free relays integrate the GX-D500 into your system. Two separate signalling paths are available.

With the test button you not only check the signal sounder. Both relays also drop out, so you can simultaneously check the connected ventilation, the valve or the message to the building management system.

Correct placement and commissioning

The GX-D500 and its sensor may only be installed in dry indoor rooms on a wall, and specifically at the location where the CO₂ is to be detected. Installation must be carried out by a qualified specialist who observes the five safety rules.

Placement

Wall mounting of the control unit

1. Loosen the four housing screws and remove the front plate. If necessary, unplug the flat ribbon cable at the connector.
2. Mount the base shell of the housing on the wall using the supplied mounting material.
3. Route the cables for mains, relays and sensor as permanent surface-mounted cables and insert them through the PG cable glands.
4. Connect mains, relays and sensor to the connection terminals, then plug the flat ribbon cable back in and screw the front plate on.

Extending the sensor cable

• Be sure to retain at least 30 to 50 cm of the original cable at the sensor
• The cable is permanently and tightly connected to the sensor and must under no circumstances be disconnected
• Install a junction box near the sensor and connect the original cable to the extension cable there
• The permissible extension length and cable cross-sections can be found in the operating instructions

Commissioning

1. If possible, ventilate the room thoroughly before putting the device into operation.
2. Apply operating voltage. The device briefly performs functional tests, the external sensor is preheated, the software checks itself and the self-test timer restarts. The display shows “CO₂: Wait / Prepairing”.
3. Move away from the sensor during the start-up phase so that your exhaled air does not falsify the start values.
4. Afterwards “Wait Sensor Fault” briefly appears, the Error LED flashes and the relays switch briefly and audibly. This is part of the start-up sequence.
5. When only the green LED is lit, the warning system is in order and ready for use.

Note: Even after a short power failure the device restarts the functional check. At first commissioning the self-test stores “Last Error 3”. This is not a real error and does not require contact with technical support.

Test the function regularly

For your safety the manufacturer recommends regularly checking the acoustic alarm sounder with the test button for proper function.

How to check the GX-D500

1. Press the RESET | TEST button. The acoustic alarm sounder is checked.
2. Both relays Re1 and Re2 also drop out. Check whether the connected technology reacts as intended.

The button test checks the signal sounder and the relay function. It alone says nothing about the condition of the sensor. Therefore have the sensor checked and calibrated regularly – see the section “Sensor and calibration”.

Behaviour in the event of an alarm

• Ventilate the room and close all valves and fittings of your CO₂ system so that no further carbon dioxide can escape
• Inform other people and instruct everyone to leave the room
• Stay calm and open all doors and windows
• Stop all use of combustion appliances and, in the case of gas appliances, operate the emergency shut-off valve
• Ensure a supply of fresh air
• Observe your operating regulations and familiarise yourself and your employees with the warning device immediately after installation

Fault indication, cleaning and maintenance

How the device reports a fault

• The fault relay Re2 drops out and informs the building management system or home automation
• The yellow “Error” LED flashes or lights up
• A short signal tone sounds every 10 seconds
• Press the SERVICE button until the display shows “Last Error” and a number. Quote this number to the technical support of Elektrotechnik Schabus, who will find a solution together with you

If the self-test results in a “not good”, the system performs up to three restarts, repeats the measurements and then decides whether a fault message is issued.

Interpreting the yellow LED correctly

Only a few faults affect the measurement of the CO₂ concentration and prevent alarming in the event of danger. There are also faults that do not affect the warning system. They can indicate adverse environmental conditions with accelerated ageing or mains voltage fluctuations. The flashing rhythms of the yellow LED are controlled by the microcontroller. If it itself has a problem, the yellow LED lights continuously. A controller problem can only be rectified at the manufacturer’s factory in Stephanskirchen; in this case contact the manufacturer.

Rectifying faults

• Press the RESET | TEST button so that the fault relay Re2 energizes again. If the fault persists, it remains energized and only drops out again in the event of a new fault
• Most faults clear themselves or when you disconnect the device from the power supply, allow it to cool for about 15 minutes and restart it
• In the meantime ensure the freshest air possible
• If there is no improvement, contact technical support

Cleaning

• Only occasionally remove dust from the device with a dry linen cloth. In the case of heavy soiling it may be slightly dampened
• Avoid the influence of moisture, such as splash or rain water, as well as dust and direct sunlight
• Do not use solvent-based cleaning agents
• Always keep the warning device away from moisture

Sensor and calibration

The device operates maintenance-free. Every NDIR sensor is subject to natural drift over time. The infrared sensor should therefore be tested regularly and calibrated annually to its zero point in accordance with the operating instructions. To do this, send the device to Elektrotechnik Schabus; the date of the next calibration can be found on the sticker on the underside of the sensor. Sensors can be sent in for checking or calibration regardless of their age. Alternatively, a USB calibration adapter cable is available as an accessory with which the operator can perform the zero-point adjustment on site. The expected service life of the sensor is more than 8 to 10 years (90 % of the sensors). This figure is not a guarantee; it serves for comparison and is based on the manufacturer’s experience.

What the display shows

When mains voltage is applied, the display greets with the manufacturer’s name and the device type. During this time the device completes all self-tests. Afterwards the main display appears with the CO₂ concentration in %.

Manufacturer’s notes

• Read the operating instructions carefully before installation and commissioning and keep them; they form part of the product
• Installation must be carried out by a qualified specialist
• Packaging material is not a toy and does not belong in the hands of children
• Intended exclusively for the detection of higher CO₂ concentrations from technical systems under pressure or from dry ice processing and storage
• Not suitable for general monitoring of indoor air for CO₂ from exhaled air
• Do not use in potentially explosive atmospheres
• Use only in dry indoor rooms, including the sensor
• The device is not approved for any use other than that described
• Intended for residential, commercial and industrial areas as well as small businesses, for example sales areas, catering, small breweries, wine cellars, workshops and public authorities
• The manufacturer is not liable for damage or losses resulting from the fact that no alarm signal is given despite elevated gas concentration
• The declaration of conformity is available for download on the manufacturer’s website

Possible accessories

A USB calibration adapter cable is available as an accessory (Art. No. 200340). With it the operator can perform the zero-point adjustment of the CO₂ sensor on site. The factory-set alarm thresholds and the warning level spacing remain unchanged. The alarm limits can only be adjusted at the factory. The device itself has no options.

Warranty, guarantee, return and disposal

The GX-D500 is covered by the statutory warranty of at least 2 years in the EU. The manufacturer Elektrotechnik Schabus additionally offers a 5-year guarantee that can be registered online. Repair and spare parts are available directly from the manufacturer, even beyond the statutory warranty. The prerequisite is that the device has been used in accordance with the operating instructions.

The GX-D500 must not be disposed of with household waste. The crossed-out wheeled bin symbol on the product reminds you to use the take-back systems so that the materials can be reused in an environmentally friendly manner at the end of their service life (WEEE Reg. No. DE91394868). Further information is available from your local waste advisory service or from the manufacturer.

Why the GX-D500 is suitable

Areas of application

• Beverage dispensing systems in gastronomy and bars
• Small and medium-sized breweries with fermentation tanks and pressurized cylinders
• Wine and fermentation cellars
• Cold rooms and technical rooms
• Rooms with CO₂ pressurized gas cylinders
• Dry ice processing and storage
• Event catering with permanently installed dispensing systems
• All systems with CO₂ from pressurized cylinders

The Schabus Profi CO₂ Detector GX-D500: Because good air knows no compromises.

Frequently asked questions