Detector Systems
Flame photometric detector (FPD)
Flame ignition problems
Two common flame ignition problems are:
A loud pop results on ignition and the flame will not light or stay lit.
If a loud pop occurs on ignition, it is usually caused by an incorrect ignition sequence. The correct ignition sequence is:
1.Open the auxiliary Nitrogen Valve if required.
2.Open the Air/Oxygen Valve fully counterclockwise (CCW).
3.Press in and hold the Ignitor Valve.
4.Open the Hydrogen Valve fully counterclockwise (CCW). On doing this, there should be a slight pop.
Note: A loud pop is caused by opening the hydrogen valve before pressing the ignitor, thereby igniting a volume rich in hydrogen. This should not damage the detector but is unpleasant to hear. Always open the hydrogen valve after pressing the ignitor.
If the FPD flame won’t light or stay lit, check/do the following:
1.Be sure there is a problem. Under some conditions, the flame lights so quietly that the pop is nearly inaudible. Also, especially in oxygen mode, the increase in signal offset on the LED display is usually only a few counts. Flame ignition is best verified by holding a mirror or shiny surface near the aluminum exhaust tube (with the rubber drip tube removed) and observing condensation (if the flame is lit).
2.If the flame doesn’t light at all, be sure the glow plug circuit is working. This is most easily done by observing the LED display, which should go to greater than 65500 counts when the ignitor switch is pressed. If the LED display doesn’t change with the ignitor switch pressed, either the circuit is open (check the pin connections at the detector flow manifold block, the lead connection on the glow plug, and the appropriate 5A fuse on the instrument’s main circuit board).
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