Is the Ascarite purge in Method 0050 required for all runs?

As you recall, the objective of the Ascarite purge in Method 0050 is to move any entrained HCl/Cl2 on the heated filter or in the optional glass cyclone back to the impingers.  This is accomplished by attaching an Ascarite scrubber to the inlet of the probe, with the filter heated to 248 F, purging the train for up to 45 minutes at a desired flowrate of 1 inch of water as indicated by the delta H manometer.  EPA has found that if visible water is observed in the optional cyclone, one can increase the temperature of the filter box to 177 C to help vaporize the water, consequently moving the entrained HCl/Cl2 to the impingers.