Honeywell MPD Series Operating Manual page 6

CAUTIONS
To maintain safety standards, regular maintenance, calibration and operation of the
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equipment by qualified personnel is essential.
Do not modify or alter the sensor construction as essential safety requirements
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may be invalidated.
When replacing sensors, dispose of used sensors in accordance with local
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disposal regulations. For more information on sensor disposal, contact your HA
Representative.
The catalytic detector element is resistant to catalyst poisons, however, abnormally
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high concentrations of halogenated hydrocarbons, vapors of heavy metals or
compounds, some silicone compounds and sulfur compounds may cause loss of
sensitivity.
» The MPD must never be used in conditions where there is insufficient oxygen to
totally oxidize the combustible gas. For most combustible gases, an oxygen level
of at least 15% is sufficient.
The sintered disc on the sensor assembly must be kept free from contaminants;
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i.e. oil and dirt.
The sensitivity of catalytic sensors is impaired by silicone compounds. Do not expose
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the sensors to silicones or silicone-based products.
The relevant site procedures must be obeyed at all times when opening the Terminal
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Housing or removing the sensor in a hazardous areas.
The sensitivity of Catalytic Sensors is impaired by silicone compounds. Do not expose
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to silicones or silicone based products.
Dismantling of a sensor or a sensor installation by other than authorized engineers
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invalidates certification.
Upward pressure on the gassing nozzle of the Weatherproof Cap forces the nozzle
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against the sinter. Rotation of the nozzle may damage the sinter if a filter is not fitted.
Direct gassing of the sensor via the nozzle on the Collecting Cone in wind speeds of
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greater than 5 meters per second may cause errors.
The calibration procedure should only be performed by qualified personnel.
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Before initial calibration allow the detector to stabilize for 30 minutes after applying
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power. When in zero and span calibration mode the current output from the detector
is inhibited (e.g. default 2mA) to avoid false alarms.
Extended or frequent exposure to elevated concentrations of combustible gases
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may affect sensor sensitivity. Verify sensor performance by frequent calibration.
Where the user calibrates any sensor using a different gas, responsibility for dentifying
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and recording calibration rests with the user. Refer to the local regulations where
appropriate.
These (meter multiplication) factors only apply to gas concentrations expressed in
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% Volume terms.
6 MPD Operating Manual