Ametek Thermox 2000 ATEX Series User Manual page 158

Hot-Wire Combustibles Detector Replacement
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7-12 | Thermox Series 2000 WDG-HPII / HPIIC - ATEX
Always use a backup wrench when working on sensor plumbing.
NOTE
To replace a hot-wire style combustibles detector, do the following (see
Figure 7-6):
Remove the detector leads from terminals E, F, H and I from the
sensor card inside the terminal box.
Loosen the compression fitting nut that holds the combustible
detector in place and remove the detector from the combustible
detector block. Save the nut from the detector because you will need
it when installing the new combustibles detector.
It is very important that you orient the new combustibles detector
correctly inside the combustibles detector block (sample flow path
must contact both detector leads at the same time). To do this, place a
mark on the edge of the combustibles detector at the 12 o'clock
position once you have determined the correct orientation (see
Figure 7-5 for correct orientation - detector elements should be
placed in detector block vertically).
Install a new combustibles detector with nut and ferrules. Be ex-
tremely careful; do not damage the detector elements when install-
ing. Ensure that the mark you made in step 3 is in the 12 o'clock
position to ensure proper orientation of the combustibles detector in
the combustibles detector block.
Reconnect the detector leads to the sensor card. The active element
wires are labeled "A" and "AC", and they connect to Terminal E and F
respectively. The reference element wires are labeled "R" and "RC",
and they connect to Terminals H and I respectively.