in normal operating mode. If there is an alarm or a malfunction
or the Air Guard is shut down, the contacts open.
When the breathing air supply is turned on, an increased CO
concentration may occur. This happens especially after the
compressor has been idle for a longer period of time. In this
case, activate the purge to restore the Air Guard to its
operating condition. To purge the line, purging must be
activated on the Air Guard touchscreen. By activating the
purge, one of the potential-free contacts (X2 terminals 21 and
23) will be closed again. The compressor must be installed at
this terminal so that the compressor can be restarted during
purging.
NOTICE
Observe the technical specifications for using the
potential-free contacts (see chapter 9).
1. Connect the potential-free contact to the external alarm
system or component.
4.2.4
Electrical connection
WARNING
The electrical system may only be installed by qualified
electricians.
1. If necessary, connect the potential-free contacts.
2. Insert the power plug of the Air Guard into the earthed
power socket.
NOTICE
It is recommended that the circuit breaker in the mains supply
line should have the following characteristics:
16 A, characteristic B.
3. Turn on the circuit breaker.
4. Close and lock the door of the Air Guard.
4.2.5
Calibration
Gas detector
CAUTION
The Air Guard must be calibrated before use to prevent
erroneous measurements.
► Calibration may only be carried out by Dräger or by Dräger
authorised technical personnel.
The electrochemical gas sensors for the Polytron gas
detectors are supplied unmounted along with the Air Guard in
order to increase the life span and must be installed before
calibration. For instructions on how to install them, refer to the
instructions for use of the respective gas detector and sensor.
The respective gas sensor must be allowed to warm up for a
while after it is inserted in the gas detector. The exact warm-up
time can be found in the corresponding instructions for use.
The gas detectors can then be calibrated. It is recommended
that the Air Guard be turned on before calibration so that the
wait time up to calibration by DrägerService of the authorised
technical personnel is as short as possible. The PIR 7200 is an
optical gas detector which does not require sensors.
1. Calibrate the zero-point as described in the instructions for
use.
2. Calibrate the sensitivity as described in the instructions for
2
use.
The calibration gas suitable for the sensor must be used to
adjust the sensitivity. Select the concentration according to the
measuring range of the sensor (see chapter 10).
Oil sensor
Calibrate the oil sensor using isobutylene as described in the
instructions for use included in delivery. This work may only be
carried out by Dräger or by authorised technical personnel.
Moisture sensor
CAUTION
The pressure must be set correctly (±1 bar tolerance).
► If it is not set correctly, this could compromise the accuracy
of the moisture sensor.
► If the pressure does not correspond to the pressure
specified in the Air Guard order, the setting of the moisture
sensor must be adjusted immediately by Dräger or by
Dräger authorised technical personnel.
NOTICE
No settings need to be made on the HP Air Guard because
the pressure is kept at a constant value by the pressure
reducer.
4.2.6
Touchscreen
It is recommended that the date and time on the touchscreen
be set correctly to ensure that the respective maintenance
intervals and measured value curves are displayed with the
correct date and time. The change to/from daylight saving time
has to be done manually (see chapter 4.4.12).
4.3
During operation
CAUTION
Risk of injury due to contaminated breathing air
The air in the pipeline system must not be used or filled during
an alarm (red indicator light) and while the Air Guard is being
purged, otherwise contaminated air may be inhaled or bottles
can get contaminated.
CAUTION
Risk of injury if hearing protection is not worn
The gas is released at a very high speed during purging and is
extremely loud.
► Hearing protection must be worn during purging.
When the breathing air supply is turned on, an increased CO
concentration may occur. This happens especially after the
compressor has been idle for a longer period of time. In this
case, activate the purge to restore the Air Guard to its
operating condition. For this reason, the Air Guard purges for
5 minutes during the start-up procedure.
If the Air Guard indicates a device malfunction (alarm), the
system needs to be purged. The Air Guard is ready to take
measurements as soon as the signal lamp on the Air Guard is
green.
Operation
en
2
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