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Bosch Building Technologies

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    How to define and Correct on DS7400 Series Report of Dirty Chamber


    The keypad displays Dirty Chamber and a point number.


    A multiplex smoke detector has failed its internal sensitivity test. 

    • a) The smoke may not be calibrated.
    • b)  May have a duplicated address


    1. Clean or replace the dirty smoke detector or chamber. (Do not use water)
    2. Plug a TC2000 Test Cable (optional) into the calibration voltage pins

    (see Figure 4).


    Connect a digital voltmeter to the TC2000 Test Cable. Connect the negative terminal of the meter to the black wire of the TC2000 and connect the positive terminal of the meter to the test cable’s red wire. The white wire of the TC2000 is not used.

    - The voltage measured by the voltmeter equals 1/2 the sensitivity (in %/ft obscuration) of the DS250.

    - Multiply the voltage by 2. The result should be within the factory marked calibration range printed on the label attached to the bottom of the detector.

    If the detector is outside of the factory marked calibration range, it should be removed and cleaned or replaced as described in Section

    5.0 Maintenance on page 3.


    - Recheck the calibration voltage measurement.

    - If the detector is still outside of the factory marked calibration range after cleaning, send the unit back to Bosch for re-calibration.

    Need to check the address of the modules

    Part numbers DS7400X, DS7400, DS7400Xi, DS7400XIVER2, DS7400XIVER3+, DS7400XIVER4, MX250, D7050, MX250TH, D7050TH

    Version history
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    Last update:
    ‎06-05-2018 07:52 PM
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