Det-Tronics NTMOS IP66/IP67 H2S Gas Detector - Manual (Page 10)

95-8670 2.1 8
MAINTENANCE
The NTMOS Detector is an industrial-grade device,
suitable for a wide variety of challenging environmental
conditions. However, a routine maintenance schedule
is recommended to ensure that the detector is in
peak operating condition at all times. To ensure top
performance, service the device as follows.
VISUAL INSPECTION
A visual inspection is recommended to ensure that
physical obstructions such as trash, debris, mud, snow,
or oil have not blocked or impeded hazardous gas access
to the detector. The frequency of a visual inspection is
determined by the application and environment.
NOTE
If the device cannot be calibrated or responds
slowly to the calibration gas, check the condition
of the hydrophobic filter and the sensing element
before replacing the detector.
FUNCTIONAL (BUMP) TEST
It is acceptable to perform a functional (bump)
verification test in place of a complete calibration if the
detector output in clean air appears stable and has been
calibrated recently.
This test involves applying calibration gas to the
detector while in normal operating mode and
confirming correct detector response. Proper
calibration requires the use of either Det-Tronics’
NTMOS calibration kit with humidification tube and
bottled H
2
S in air (p/n 010272-001), or the ampoule
calibration kit (p/n 007098-005). It is the operator’s
responsibility to bypass any and all system alarm
output devices, if necessary, prior to conducting the
bump test. If the bump test results are not acceptable,
then a complete calibration must be performed.
The NTMOS H
2
S Detector must be “functional tested”
using only Det-Tronics’ humidification tube kit or
the ampoule kit. All ampoule functional tests must
be performed using the Det-Tronics H
2
S Mixer with
thumb screw ampoule breaker and internal mixing
fan (p/n 007067-001). When using either method to
perform a bump test do not use bottled H
2
S with
nitrogen . When performing calibrations, validate the
expiration date of the gas cylinder.
DETECTOR REPLACEMENT
The NTMOS Detector is not repairable. If calibration can
no longer be properly performed, the detector must be
replaced.
The area must be de-classified and power to the detector
should be removed prior to replacing the detector in a
hazardous area.
Follow the procedure below to replace the detector.
1. Remove power to the transmitter or controller prior to
replacing the detector.
2. Remove the transmitter/termination box cover.
3. Disconnect the detector wiring, then unscrew it from
the conduit entry.
4. Thread the wires for the replacement detector
through the conduit entry and screw the detector into
the conduit entry. Connect the detector wires to the
appropriate terminals.
5. Replace the junction box cover.
6. Re-apply power. Refer to “Startup Procedure.”
An adequate supply of spare detectors should be kept
on hand for field replacement. For maximum protection
against contamination and deterioration, they should
not be removed from the original protective packaging
until the time of installation. To ensure maximum
storage life, detectors should be stored in their original
packaging, or if the bag has been opened, with the
plastic cap and desiccant capsule in place. Always
calibrate after replacing the detector.