User Manual

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Siemens Differential pressure sensors QBM65…/C, QBM75…/C CA1N1919E
Building Technologies 27.08.2010
Horizontal mounting (with the hinged cover at the top or bottom) is NOT
RECOMMENDED. If horizontal mounting cannot be avoided, account must be taken of
deviations in the measured value (see "Factory calibration" below).
This mounting position is not allowed for QBM75-1U/C.
70006
+–
If the pressure connection nozzles face up-
wards, or are at a lower level than the duct
probes, condensation can collect inside the
unit, causing damage to the sensor.
When mounting on 35 x 7.5 top hat rails to DIN, mounting bracket AQB21.2 is required
which is available as an accessory item. The sensor snaps on the bracket.
For direct mounting on lagged ducts, the sensor can be fitted with an AQB2000 mount-
ing bracket (see "Accessories"). A 2 m length of plastic tubing is supplied with the sen-
sor and can be adapted to the duct probes on site. Connect the tubing from the lower
pressure side to pressure connection nozzle 'P2' or ' – '.
Factory calibration
The values given under “Technical data” are valid only when the differential pressure
sensor is mounted vertically. Should it be necessary to mount the sensor horizontally,
i.e. with the hinged cover at the top or bottom (NOT RECOMMENDED), account must
be taken of the following deviations in the measured value:
Recommended orientation:
Hinged cover in vertical
position.
Signal as per factory calibration
Mandatory with QBM75-1U/C.
NOT RECOMMENDED:
Hinged cover facing downwards.
Signal approx. 13 Pa above actual
pressure.
Not allowed with QBM75-1U/C.
NOT RECOMMENDED:
Hinged cover facing upwards.
Signal approx. 13 Pa below
actual pressure.
Not allowed with QBM75-1U/C.
+–
+–
70007
+–
Recalibration service
Siemens provides a recalibration service for these pressure sensors. Under ‘normal’
conditions, recalibration should be repeated at 12-month intervals (or in accordance
with the relevant statutory requirements). A recalibrated sensor should not be stored for
more than 12 months (or it should be commissioned within that period). In the case of
sensors which are over 10 years old and/or in poor condition, Siemens reserves the
right to refuse recalibration and readjustment.
The recalibration service
1)
comprises the following elements:
• Calibration
2)
with record of values
• Sensor test including repairs and replacement of worn parts.
• If necessary, readjustment
3)
and recalibration
• Completion and supply of a new calibration certificate
• Despatch and registration (original sensor returned to the customer)
1)
Handling and invoicing reference S/QBM65.../C or S/QBM75.../C
2)
The sensor is compared with a measuring standard. Deviations are recorded but not corrected
3)
The sensor is compared with a measuring standard and any deviations noted are corrected
Caution
.
.
.
Services included