PGC5000
PGC5000 Series Service Instructions
7 Subassembly repair
SI/PGC5000-EN, Rev B
58
6. Repeat this measurement for each of the other three filament wires. If all resistance measurements are correct, go to
"Connecting the Filaments." If any resistance is too low, go to step 8.
7. If the resistance measurement is approximately 20 ohms, filament being tested is contacting the internal wall of the
detector cell cavity. When this occurs, carefully loosen the gland of the suspect filament. Continue to loosen by hand and
withdraw first the gland, then the filament from the detector cell body (taking care not to touch or damage the filament).
8. Inspect the filament for damage or bending. If it is damaged, the filament pair will have to be replaced.
9. If the filament is slightly bent, use small needle nose pliers to gently and carefully bend it straight.
10. If the filament orientation now appears to be correct, reinstall the detector filament and repeat the complete checkout. If
it fails again, replace the detector filament pair and repeat the checkout.
11. If the filament is damaged during this attempted correction process, the filament pair will have to be replaced.
7.3.4 Leak test
1. Restore carrier to the analyzer and establish carrier flow to both the measurement and reference ports of the detector.
2. Verify carrier and reference flow using a flow meter. Typically the flows should be 30 to 40 cc per minute if packed
columns are used, 10 to 15 cc per minute if 0.53 mm ID capillary columns are used, and 3 to 5 cc per minute if 0.32 mm ID
capillary columns are used.
3. Cap the TCD vents to pressure up the TCD.
4. Test for leaks around the detector filament gland nut with a nonconductive liquid leak detection solution. Correct all leaks
before proceeding.
5. Shut off the carrier supply to the analyzer.
6. Gently remove any excess leak detection solution with a soft cloth or tissue and blow dry with 15 psig clean dry air, helium
or nitrogen.
7. Slowly loosen and remove the cap nuts installed in step 3.
7.3.5 Connecting the filaments
1. Roll the ends of each stripped harness wire between your thumb and index finger to tightly spiral wrap the wire ends.
2. Using a 40 watt soldering iron and approved high temperature solder, “tin” each of the harness wire ends.
3. Roll the ends of each stripped filament wire between your thumb and index finger to tightly spiral wrap the wire ends.
4. Using a 40 watt soldering iron and approved high temperature solder, “tin” each of the filament wire ends.
5. Install approved heat shrink over each of the four filament wires, and slide it as far from the free wire end as possible.
6. Select a harness assembly wire with the “R” label designation and overlap the “tinned” ends of this harness wire with one
of the reference filament wires.
7. Solder the wires using a 40 watt soldering iron and approved high temperature solder. Apply solder sparingly, allowing it
to flow evenly. Do not overheat the solder or a high resistance connection could result.
8. Repeat steps 6 and 7 for the remaining harness wire labeled “R” and reference filament wire.
9. Repeat steps 6 through 8 for harness wires labeled “M” and the measurement wires.
10. Slide heat shrink over each connection and shrink with a heat source.
7.3.6 Potting the filaments (CENELEC and CSA only)
Perform this procedure if you know that your analyzer is constructed to CENELEC or CSA specifications or if the existing
detector filament is potted.
1. Gently slide the insulation sheath out of and away from the gland nut.
2. Using a syringe filled with Silastic compound “Dow 736 RTV,” completely fill the gland cavity with the Silastic compound.
3. With the insulation still pulled away from the gland nut, use needle nose pliers to install the wire spreader.
4. Separate and insert filament wires into the slots on either side of the spreader. The spreader should be positioned
between the end of the sheath insulation and the back of the gland nut.
5. Press the spreader into the recess in the gland nut. The retainer must be installed such that it is not in any way tilted. It is
normal for the retainer to protrude slightly from the gland recess.
6. Slide the sheath insulation toward the wire spreader until it contacts the face of the spreader.
7.3.7 Re-installing mounting bracket cover
1. Reinstall the insulating material.
2. Reinstall mounting bracket cover.
3. Use a Phillips screwdriver to secure the mounting bracket cover with the two Phillips head screws removed in “Removing
the filament” procedure.
