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6.0
Periodic Testing
Calibration is very important in determining the
detector's continued operation. Depending on local
regulations, the frequency of calibration testing might be
required more than once a year. NFPA Standard 72
recommends a calibration test at installation and every
other year thereafter. Perform functional testing annually.
Notify all concerned parties before any fire
alarm system maintenance or testing and
again after test completion.
To meet NFPA 72 requirements, check calibration using
any of the tests described in Section 6.1 Visual Check
through Section 6.3 Voltage Measurement Test. These tests
confirm whether or not the detector is within its
factory-marked calibration range.
6.1
Visual Check
The D285DH includes the Chamber Check Automatic
Trouble Indication, allowing it to automatically indicate
if its calibration is out of the factory-listed range.
Visually inspecting the D285DH and checking the LED
flash rate meets the NFPA guidelines for sensitivity
testing.
If the calibration is out of range for more than 24 h, the
D285DH alarm LED flashes once per second. The LED
flashes once every 4 sec when the detector is operating
normally.
Visually check all detectors before resetting the power.
Disconnecting the power erases this indication. If the
detector was reset within the last 24 h, or you are unsure
of the last reset time, perform the Magnet Test or
Voltage Measurement Test to confirm sensitivity.
6.2
Magnet Test
Place a magnet horizontally against the recess in the
duct housing cover and observe the LED.
•
If the detector is within the factory-marked
calibration range, it goes into alarm and the Alarm
LED latches ON.
•
If the detector is too sensitive, the LED on the head
flashes six times rapidly (once every 1/2 sec). Then
the detector goes into alarm.
•
If the detector is not sensitive enough, the LED on
the head flashes four times slowly (once every 2 sec).
Then the detector goes into alarm.
•
If the detector is not operational, it does not signal an
alarm.
Bosch | 6/04 | 49323C
D285DH | Installation Instructions | 6.0
6.3
Voltage Measurement Test
1. Plug a D1005 Test Cable (optional) into the
calibration voltage pins (Figure 4).
Figure 4: Calibration Voltage Pins
1 - Calibration voltage pins
2. Connect a digital voltmeter to the D1005 Test
Cable.
3. Connect the meter's negative terminal to the
D1005's black wire and connect the meter's positive
terminal to the test cable's red wire. The white wire
of the D1005 is not used.
4. If a D344-RT or D344-RL is installed, use voltage
monitor jacks. The voltage measured by the
voltmeter equals 1/2 the detector's sensitivity
(in %/ft obscuration).
Multiply the voltage by 2. The result should be
within the factory-marked calibration range that is
printed on the label attached to the bottom of the
detector.
5. If the detector is outside of the factory marked
calibration range, remove it and clean it as
described in Section 5.0 Maintenance on page 4.
6. Recheck the calibration voltage measurement.
7.
If the detector remains outside the factory-marked
calibration range after cleaning, return it to Bosch
for re-calibration.
Periodic Testing
1
5
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