Huberg METREX2 User manual

METREX2
USER MANUAL
VERSION 2.5

Form creation date: 01.04.2008
Document creation date: 13.01.2020
2 / 18
Our products for gas safety
The professional instrument for the
detection and localization of gas leaks
for CH4 e C3H8 with Bluetooth and
GPS.
There is also a version with Ethane
sensor.
Set of probes for all purposes
to use with HUBERG
instruments: carpet probe,
sucker probe,flexible probe,
hand held probe and
extendible probe.
The new portable instrument for gas
leak detection and localization of gas
leaks for CH4 e C3H8 and for toxic gas
(O2, CO, H2S)
Portable instrument for
verifying the calibration and
the flow rate.
Instrument for the personal safety, for
HC (CH4 e C3H8) and toxic gases (O2,
CO, H2S).
Portable instrument for the
detection and localization of
micro gas leaks (CH4 e C3H8)
and for personal safety (O2,
CO, H2S).
Portable instrument for the detection
of methane and propane.
The portable gas
chromatograph for the
measurement and analysis of
odorants in gas distribution
networks.
Explosion-proof vacuum aspiration
pump to drain residual gas from the
ground.
Instrument for the
measurement of THT in
network.
Special vehicles for preventive and systematic gas leak
survey in real-time (selectivity IR methane detection, GPS
on board). System controlled by computer and all the
survey can be connect to the company cartographical
system.

Form creation date: 01.04.2008
Document creation date: 13.01.2020
3 / 18
INDEX
Our products for gas safety........................................................................................................................................ 3
1.0 GENERAL DESCRIPTION ......................................................................................................................................... 5
2.0 KEYBOARD AND CONNECTIONS ............................................................................................................................ 6
3.0 INSTRUMENT PERFORMANCE ............................................................................................................................... 7
3.1 HOW TO SWITCH ON INSTRUMENT .................................................................................................................................... 7
3.2 PPM AND VOL MEASURING RANGES ................................................................................................................................. 8
3.3 LEL MEASURING RANGE .................................................................................................................................................. 8
3.4 ALARM ........................................................................................................................................................................ 9
3.5 DATA REGISTRATION (OPTIONAL) ................................................................................................................................. 10
3.6 AUTO ZEROING ............................................................................................................................................................ 11
3.7 DISPLAY ILLUMINATION ................................................................................................................................................. 11
3.8 RECHARGING OF BATTERIES ............................................................................................................................................ 11
3.9 BATTERY STATUS VISUALIZATION ..................................................................................................................................... 12
4.0 GAS TYPE SELECTION (OPTIONAL) ...................................................................................................................... 13
5.0 PUMP BLOCK ...................................................................................................................................................... 13
6.0 MAINTENANCE AND PERIODICAL CALIBRATION ................................................................................................. 14
7.0 WARRANTY ......................................................................................................................................................... 14
APPENDIX A – SAFE USE OF THE INSTRUMENT ......................................................................................................... 21
Appendix B - Important information for correct disposal of the electric and electronic equipment ............................... 23

Form creation date: 01.04.2008
Document creation date: 13.01.2020
4 / 18
1.0 GENERAL DESCRIPTION
The METREX2 is a digital gas detection instrument which can be used for systematical survey of
natural and town gas networks and for leak detection outside as well as inside of buildings.
Due to its compact design and modest size the METREX2 can be transported easily and the large
LCD-display with the instantaneous reading of the gas concentration measured makes it simple to
work with this device. Furthermore, a selection of various types of probes makes it possible to use
it at points otherwise difficult to reach.
A microprocessor manages all the instrument performances: control of the sensor for the detection
of gas concentrations, the functions of the instrument which can be commanded by keyboard,
management of alarms, registration of data and serial communication for download on PC of
memorized data.
This unit is designed to comply the actual ATEX directive.
METREX2 works with a group of ecological harmless, rechargeable nickel metal hydride batteries
which allow - when fully charged - a working autonomy of at least 8 hours under normal working
conditions and a constant temperature of 20 °C.
Important: Recharging of batteries and I/O connection must be carried out in safe environments.
The METREX2 has three measuring ranges: PPM (part per million), %Vol (volumetric) and the LEL
(Lower Explosion Limit).
The METREX2 has three sensors: one semiconductor sensor, one pellistor pair sensors and one
volumetric thermal conductivity pair sensors.

Form creation date: 01.04.2008
Document creation date: 13.01.2020
5 / 18
2.0 KEYBOARD AND CONNECTIONS
Figure 1
1. Switch OFF button
2. Data recording button
3. Switch ON/OFF acoustic signal button
4. Switch button PPM/VOL/LEL button
5. Auto zeroing button
6. 220 V~ connection LED
7. Battery recharge LED
8. ON/OFF acoustic signal LED
9. Alarm threshold LED
10. VOL scale LED
11. Display
Figure 2
1. Air outlet
2. Quick coupling for probes
3. Buzzer
4. Socket for battery charger/serial port for data download
5. Cover

Form creation date: 01.04.2008
Document creation date: 13.01.2020
6 / 18
3.0 INSTRUMENT PERFORMANCE
3.1 How to switch on instrument
In order to switch on the instrument push, for
at least three seconds, one of the buttons at
the lower part on the right of the keyboard
(fig.1 button (2), (3), (4),(5)). When switched
on, a serial number of the instrument will be
shown on the display (fig.3), followed by an
acoustic signal.
Subsequently the display will show “Px.x”
(software version) and “CAL” (calibration in
progress, fig.4 and fig.5)
fig. 3
fig. 4
fig. 5
The phase of warming up and auto calibration
takes about 1 minutes after switching on the
instrument.
When finished, the device automatically
changes to the PPM scale.
ATTENTION:
Switching on of the instrument must take
place in place free from gas.

Form creation date: 01.04.2008
Document creation date: 13.01.2020
7 / 18
3.2 PPM and VOL measuring ranges
The METREX2 has the two measurement scales PPM and VOL%.
After switching the instrument on it starts automatically in the PPM range.
The PPM range visualizes concentrations from 0 to 9900 PPM (parts per million),
whereas the volumetric scale measures from 0 to 100%.
A changeover between the two ranges is possible by pressing the PPM/VOL button
(4) (fig.1 and fig.7).
If a concentration of 1% VOL occurs while working in the PPM range, the instrument
automatically changes over to the volumetric range. Inversely a changeover from
the volumetric to the PPM scale is only possible by pushing the PPM/VOL button
and is not executed automatically. Furthermore, a changeover from VOL to PPM is
only possible if the gas concentration is below 10000 ppm (1%). When the
volumetric range is chosen, the corresponding LED (10) (fig.1 and fig.8) is lit.
fig. 7
fig. 8
3.3 LEL measuring range
The METREX2 has the LEL scale (fig.10) which is activated by pressing the PPM/VOL
button (4) (fig.1 and fig.9) for more than 2 seconds. If the acoustic alarm is
activated, a signal tone is emitted. A changeover from the LEL scale is only possible
manually. For switching back to the PPM or VOL range the same button has just to
be pushed briefly. fig. 9
fig. 10
For CH4, the measuring LEL range (0-
100%) corresponds to a range of 0-5%
(100% LEL = 5% VOL) of the volumetric
scale.

Form creation date: 01.04.2008
Document creation date: 13.01.2020
8 / 18
3.4 Alarm
fig. 11
fig. 12
fig. 13
fig. 14
fig. 15
When switching on the METREX2, the acoustic alarm is activated and the LED (fig.11) is lit
up.
The user can deactivate and reactivate it by pressing the alarm ON/OFF button (3) (fig.1 e
fig.12) according to his requirements.
If the acoustic alarm is deactivated but the concentration measured exceeds the preset
alarm limit, in any case the optical alarm LED (9) (fig.1 and fig.13) blinks.
The alarm thresholds are adjustable both in the PPM and in the VOL range. Press button
(3) (fig.1 e fig.12) for more than 2 seconds to see the alarm limit actually set. It can be
altered by holding this button (3) pressed and additionally pressing the PPM/VOL button
(4) (fig.1 and fig.14) for increasing or the zero-button (5) (fig.1 and fig.15) for decreasing
the value.
Because also the acoustic alarm is switched on or off with button (3) it is recommended
to check the wanted display mode after adjusting the alarm limit.

Form creation date: 01.04.2008
Document creation date: 13.01.2020
9 / 18
3.5 Data registration (OPTIONAL)
During the surveys there is the possibility to record up to 500 measurement
readings in the internal memory of the METREX2. If the record button (2) (fig.1 e
fig.16) is pressed during the normal function of the METREX2, the actual value on
the display is 'frozen in'. The displayed value starts blinking and an acoustic signal
is given to indicate the special status. Additionally the pump is switched off.
fig. 16
The instrument will stay in this mode until any other button (other than button (2)) is pressed which
will restore the normal function. But pressing button (2) again will show the number of the last
measurement saved (n 0 for example means that no data storage was done so far). By pressing of
button (2) for a third and last time, the new reading will be recorded consecutively in the internal
memory and with that the instrument returns to the normal function.
The following procedure makes it possible to show all recorded readings on the display of the
instrument, e. g. before transferring the data to a computer. Press the record button (2) two times
and the number of the last reading will be displayed. By pressing the buttons (4) or (5) (see fig. 1) all
savings can be run through forward or backward. When the wanted record is reached, the value of
the reading will be shown by holding the button pressed for min. 2 seconds and as long as the button
is held down. To return to the normal function without saving any data press button (3).
To cancel all records connect the METREX2 to the battery charger and to the power supply (recharging
mode). Press the buttons (2) and (5) (see fig.1) simultaneously for min. 2 seconds.
fig. 17
The instrument then emits an acoustic
signal and shows at the display the
writing - - - - (fig.17), to confirm the
cancellation.

Form creation date: 01.04.2008
Document creation date: 13.01.2020
10 / 18
3.6 Auto zeroing
fig. 18
By pressing the zero button (5) (fig.1 e fig.18), the instrument is set to 0 (zero).
The zeroing function is executable only at gas concentrations below 1800 ppm.
3.7 Display illumination
To activate or deactivate the background display illumination the
buttons (3) and (5) (see fig.1 and fig.19) have to be pressed
simultaneously.
fig. 19
3.8 Recharging of batteries
IMPORTANT
To recharge the batteries solely use the HUBERG battery charger supplied with the METREX2. Make
sure that the instrument is switched off, if it is not, do that. Connect the battery charger to 220V
power supply and insert the plug into the socket of the METREX2 (4) (see fig. 2). The instrument
recognizes the connection and changes to recharging mode automatically, even if the device is
switched off. During the recharging procedure the charging voltage is shown on the display (fig. 22).
This procedure must be carried out only in a safe environment
fig. 20
fig. 21
Two LED signs will be lit:
connection to power supply (fig.20) and charging of the batteries (fig.21). The
second LED blinks fast during the recharging process and slow, when fully
charged. The time needed to recharge the batteries is approx. 10 to 12 hours.