Jesco GW 702, Руководство по эксплуатации

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24 | Operating Manual GW 702 | Maintenance
13.3 Functional test of the sensor with test gas application
• To test the zero point ambient air is used (free of measuring gas, without flammable substances),
otherwise synthetic air.
• Only certified test gases may be used within their shelf life.
• The actual concentration must be known to 2% relative to the bottle value.
• The test gas concentration is in the middle of the measuring range or slightly above the maximum
alarm threshold, at any rate below the measuring range limit.
• Test duration: 0.5 to 1.0 l/min via calibration adapter for at least 2 minutes
• Further information: DIN EN 45544-4, BG Chemical information BGI 836 (bulletin T021). In addition
there are national regulations for determining maintenance intervals.
13.4 Replacing the fuse
The devices are equipped with an internal fuse that can be replaced if required. A spare fuse is included in
the scope of supply. It is located in the terminal cover.
1. To replace the fuse, unscrew and lift up the front of the device. The fuse is located in the lower right
area. It is held in place on with a bayonet catch.
2. Turn the catch anticlockwise, until the fuse jumps out.
3. Replace it with the spare fuse and fix it in place by turning the catch clockwise.
4. Replace the front of the device and screw it firmly.
WARNING!
Ensure that the device is de-energised before opening it.
13.5 Display Contrast
For devices in wall-mounted housing the display contrast can be adapted to the actual lighting conditions by
means of a potentiometer. The potentiometer is marked in the wiring diagram with "Display".
13.6 Power supply backup system (accessory)
The backup system battery is maintenance-free.
13.7 Disposal
The equipment was manufactured in accordance with the ROHS guideline and the waste electrical equip-
ment legislation. The manufacturer will take care of disposal if the equipment is returned free of charge. It
should not be disposed of as domestic waste!