Model DM-100
DM-100 Instruction Manual
Rev. 3.5
Page 20 of 41
4.
Service and Maintenance
Calibration Frequency
In most applications, monthly to quarterly span calibration intervals will assure reliable detection. However,
industrial environments differ. Upon initial installation and commissioning, close frequency tests should be
performed, weekly to monthly. Test results should be recorded and reviewed to determine a suitable
calibration interval.
Visual Inspection
The Sensor should be inspected annually:
•
Inspect the sensor for signs of corrosion, pitting, and water damage.
•
Remove the Splash Guard and inspected it for blockage, broken, cracked, or missing pieces.
•
For H2S Sensor assemblies, inspect DM-100 Bottom Housing Assembly with integral filter (PN 602-
003552-100) for blockage of filter material.
•
Inspect inside of the Junction Box for signs of water accumulation, signs of corrosion.
•
Check wiring to ensure there are no loose or pinched wires and all connections are clean and tight.
Condensation Prevention Packet
A moisture condensation prevention packet (PN 960-202200-000) should be installed in every explosion proof
Junction Box. The prevention packet will prevent the internal volume of the J-Box from condensing and
accumulating moisture due to day-night humidity changes. This packet provides a critical function and should
be replaced annually.
4.1
Replacement of Plug-in Sensor
NOTE
It is not necessary to remove power while changing the plug-in toxic gas sensor in order to
maintain area classification, since it is intrinsically safe.
NOTE
Only replace the plug-in sensor with an authorized DM-100 family of gas sensors.
1.
Use a
1
/
8
" Allen wrench to release the locking cap head screw that locks the ITM and Splash Guard
Adapter together.
NOTE
One turn will suffice. Do not remove cap head screw completely.
2.
Unthread and remove the Splash Guard Adapter and Splash Guard from the ITM.
3.
Gently pull the plug-in sensor out of the ITM. Orient the new plug-in sensor so that it matches with the
female connector pins. Use the alignment marks provided to assure alignment is correct. When
properly aligned, press the sensor in firmly to make the proper connection.
4.
Thread the Splash Guard Adapter onto the ITM to a snug fit and tighten the locking cap head screw
using the
1
/
8
" Allen wrench. Reinstall the Splash Guard.
5.
Check and perform zero calibration and span calibration as per Section 3.3, Calibration.
