seitron 7900 Portable Combustible Gas Detector Instruction Manual

7900

DIGITAL HANDHELD GAS LEAKAGE DETECTOR

• Powered with Li-Po 3,6V – 2Ah rechargeable battery pack
• User configurable parameters
• Acoustic and optical indication in case of alarm
• Auto-shut-off function

OVERVIEW

This device is a digital handheld gas leakage detector, equipped with an external whip (for reaching the point in which the leakage is likely to happen) at whose end is mounted a gas semiconductor sensor for detection of low concentrations of hydrocarbons in gas appliances and pipes.

WARNING!
This device is not a measurement instrument.

This device can detect either Methane (CH4) or LPG (a mixture of isoButane and isoPropane, but generally to several types of Hydrocarbons.
The gas concentration is shown through the 4-digits LCD, as well as through a bar-graph ranging from 0 to 100% of the full scale. The instrument is featured with the auto zero and selfshutdown functions.

DETECTOR POWER SUPPLY

The detector is featured with an internal Li-Po rechargeable battery pack.
The recharge is made by connecting an external power supply (5V, min.0,5A/h – not provided) to the USB Type B connector. In case of necessity it is possible to recharge the
detector battery by connecting it to the PC or using a power bank, as long as it has a 5 volt output and a minimum current of 0,5A/h.
WARNING!
THE INSTRUMENT IS SENT WITH A MEDIUM LEVEL OF BATTERY CHARGE, IT IS ADVISED TO PERFORM A COMPLETE BATTERY CHARGE CYCLE, WHICH LASTS 4 HOURS. IT IS ADVISED TO PERFORM THE RECHARGE AT A ENVIRONMENT TEMPERATURE INCLUDED IN THE RANGE 10 °C .. 30 °C.
The device is featured with two led placed on the front cover, and they provide the following information when charging the battery pack:

| RED LED (1)| GREEN LED (2)
---|---|---
Battery charging in progress| On| Off
Battery charging complete| Off| On
 Battery pack not working or broken.| On| On

TECHNICAL FEATURES

0.00 .. 1% VOL CH4
0.00 .. 20% LEL CH4
0.00 .. 1.800 ppm LPG
(isoC4H10)
Resolution:| 1ppm
Response time:| < 1 s
Sensor type:| semiconductor
Pre-warm up time:| 45 s
Self-shutdown time:| OFF, 1 .. 30 minutes
 Display:| LCD
Protection grade:| IP 30
Operating temperature:| 0°C .. +45°C
Storage temperature:| -20°C .. +70°C
Humidity limits:| 20% .. 80% RH non-condensing
Case: Material:| ABS HB self-extinguishing;
Color:| Dark blue
Dimensions:| 72 x 151 x 37 mm (L x A x P)
Flexible sensor length:| 270 mm
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Included accessories:| Shoulder bag.
USB type B cable (for battery charging).
Accessories on request:| Power supply 5V, min. 0,5Ah

COMMANDS DESCRIPTION

‘ ‘ On/Off key
In order to turn the instrument On or Off press the ‘ ‘ key. When the instrument is turned on the instrument plays a short beeping sound and starts the sensor pre-heating phase, which lasts 45 seconds.
During this phase the instrument displays the word ‘HEAT’ and the remaining time before the end of it.
When the pre-heating is terminated the auto-zero phase is initiated, lasting 6 seconds and identified with another short beeping sound. Once also this is terminated, another prolonged beeping sound indicates the full functionality of the instrument.
During normal operation, while no gas is detected, the instrument will issue a short beep every 2 seconds.
In case a leakage is detected, the rate of the sound will be higher accordingly to the measured concentration.
The instrument is factory set with the auto-shut-off feature turned on and the relevant time set to 10 minutes.
This means that the instrument will automatically turn off after ten minutes from turn-on.
A temporary turn-off for this feature (until the first manual turnoff) can be accomplished by pressing the ‘ ‘ key for at least 4 seconds during the turn-on phase. In order to turn the instrument off please press the ‘ ‘ key: the action is confirmed with three short beeps issued in sequence.
‘ >0< ‘ AUTOZERO key.
When this key is pressed (an the instrument is on) the autozero procedure is initiated.
As previously explained, the auto-zero time is 6 seconds long, stressed with a beeping sound and with 4 ‘0.000’ digits flashing on the LCD.
During this phase the instrument samples the actual gas concentration and assumes that as a zero baseline for any following measurement.
When this phase is terminated, the instrument will sound a prolonged beeping sound.
AUTOMATIC Zero drift adjustment
In absence of gas the instrument continuously checks its zero level and performs an automatic drift adjustment, provided the variation is maintained within some limits.
This compensation is transparent for the user and it is performed every 2 seconds in order to compensate any possible sensor drift mostly due to temperature variations.
When the sensor detects the presence of gas it abandons this compensation procedure and switches to the gas detection operation.
‘ H ‘ Hold key
When the ‘H’ key is depressed, the ‘HOLD’ mode is started, during which the actual read value is ‘frozen’ on the lower 4 digits display. When in this mode the instrument truns the label ‘HOLD’ on and issues a short beep.
During this mode the upper 4-digits display will keep on showing the current measured concentration value (thus following the concentration variations), meanwhile the lower 4 -digits display shows the ‘frozen’ value.
If the ‘ H ‘ key is again depressed the instrument will exit from the ‘HOLD’ mode, sounding a short beep as a confirmation.
‘UNIT’ Measurement Unit Key.
When this key is depressed the measurement unit in which the display reading is expressed is selected.
Every time the ‘UNIT’ key is further depressed, the instrument will cycle among the available measurement units, according to the following sequence (Starting with the unit currently selected):

= > ppm => %vol => % L.E.L. => ppm =>

every time the unit is changed, the choice is automatically stored in the instrument memory, so that during the next instrument turn-on this will be the default unit.
‘ SET ‘ key
When this key is kept depressed for at least 3 seconds a mode is entered in which the user can set the generall parameters for the instrument operation.
These parameters are three and the user can switch between one and the following by pressing the ‘SET’ key. Once a parameter is selected, its value can be modified with the following keys:

‘FUNC’ Key:| Increases the value (if numerical) or switches between On and Off cyclically (if nonnumerical).
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‘UNIT’ Key:| Decreases the value (if numerical) or switches between On and Off cyclically (if non-numerical).

Parameters which can be adjusted are the following:
P1: Acoustic Feedback Enable/Disable
This parameter is identified with the label ‘SEt 1’.
Its value enables or disables the internal buzzer for the acoustic feedback.
Press the ‘UNIT’ or the ‘FUNC’ key to change the actual value.
The instrument is factory set with the feedback enabled (Set 1=On).
P2: Auto-Shut-Off Time.
From parameter ‘Set 1’ if the key ‘SET’ is further depressed once, the user gets access to parameter ‘SEt 2’ which allows to change the auto- shut-off time.
The ‘UNIT’ key decreases the current value, meanwhile the ‘FUNC’ key increases it.
The allowed values for this parameter are in the range 1 .. 30 minutes in 1-minute steps.
In order to disable this feature (instrument turned on until a manual turn- off) the user must increase or decrease the parameter value until the label ‘OFF’ is set.
P3: Buzzer on Alarm Enable/Disable.
From parameter ‘Set 2’ if the key ‘SET’ is further depressed once, the user gets access to parameter ‘SEt 3’ which allows to enable or disable the buzzer sound in case of an alarm.
Press the ‘UNIT’ or the ‘FUNC’ key to change the actuall value.
The instrument is factory set with the alarm buzzer enabled (Set 3=On).
From this parameter a further action on the ‘SET’ key results in quitting the parameters configuration mode, together with the storage in the instrument memory of the  preferences just set.
OVERRANGE FUNCTION
This function, active any time, continuously checks for the measured concentration to remain within the instrument full range limits.
Should the full range value be exceeded, the internal buzzer will start beeping at the maximum repetition rate and, at the same time, the ‘ALM’ symbol will be turned on and the lower display will show the label ‘OFL’ (overflow).
LOWBATT FUNCTION
The instrument continuously analyses the battery level and, in case this is found below a certain value, the low-level battery icon ‘ ‘ is shown in the upper right side of the display. When this symbol is turned on, the instrument is still perfectly operational.
After this, when the battery voltage falls below another critical level, the **words ‘Lo bAtt’ are shown on the display and the operation of the instrument is stopped: the only action allowed to the user is the turn-off.
When the instrument is further turned-on, if the supply voltage is in the valid range, all the functions are enabled again. For batteries replacement please follow the directions explained in the paragraph ‘Preliminary Operations’.
BUZZER
This instrument features an internal buzzer for both the purpose of an acoustic indication of the measured concentration and for an acoustic feedback on some user
actions.
When the instrument is detecting a gas concentration higher than zero, the repetition rate of the ‘beeps’ increases according to the concentration level.
SENSOR FAIL
The instrument periodically checks the sensor status. In case the latter is found defective, the buzzer sound is set to continuous (when the Buzzer Alarm feature is Enabled) and the words ‘SEnS FAIL’ are shown on the display.
WARRANTY
** In the view of a constant development of their products, the manufacturer reserves the right for changing technical data and features without prior notice.
The consumer is guaranteed against any lack of conformity according to the European Directive 1999/44/EC as well as to the manufacturer’s document about the warranty policy.
The full text of warranty is available on request from the seller.

Seitron Americas Inc.
4622 E. Street Rd.
Trevose, (PA) 19053 USA
Tel.: 215-660-9777
Fax.: 215-660-9770
E-mail: service@seitronamericas.com
http://www.seitronamericas.com

References

• Homepage - Seitron Americas

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