Cleaning/Replacing The Fpd Jet - HP 5890 Series II Plus Reference Manual

Preventive Maintenance
Flame photometric detector
NOTE: Once installed, the ferrule cannot be removed from the liner for
reuse unless both parts are still warm.

Cleaning/replacing the FPD jet

If a response problem is encountered (sensitivity, noise, selectivity), the
FPD jet should be inspected for deposits and, if necessary, cleaned or
replaced. To service the jet properly, the detector module should be
removed from the instrument, followed by appropriate service:
1. Turn off power to the gas chromatograph and disconnect the main
power cord. Remove the detector covers.
2. Turn off hydrogen, air (or oxygen) and auxiliary nitrogen supplies to
the detector (manifold on/off valves). For convenience, carrier flow
may be left on. Allow time for heated zones to cool to safe
temperatures.
3. Remove the photomultiplier tube (PMT) assembly from the detector
module; also remove the filter. Set both in a safe place. Also, remove
exhaust tubing (1/4•inchswage fitting) and the chimney assembly
(two M4 screws on sides). Then loosen the U clamp that locks the
burner to support bracket (Part No. 19256•00080),and disconnect the
jet assembly from the transfer line tube. Carefully lift the detector
module vertically from the transfer tube so as not to damage the fused
silica liner. See Caution and WARNING notes which follow.
Note: It is unnecessary to disconnect any plumbing, ignitor leads, or
the heater/sensor. Leave all attached and disconnect the detector
block from the transfer line at the 1/4•inchswage fitting; then gently
lift block and rotate it enough to access the jet.
4. Remove and inspect the jet assembly. Use a suitable wire to remove
any deposits.
5. This is also an ideal time to inspect/clean the glow plug (see Flame
ignition problems) and inspect/clean the quartz windows (see
Cleaning/replacing windows, filter, seals).
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