Kyle, Gerardo - 

Vented Vertex and HAM6 volumes.  Venting very slow -> Discovered too large of a pressure drop across desicant tower after-filter.  Replaced filter element.  Filter was clogged with activated alumina powder from desicant.  Flow seemed normal for an hour or so then seemed to fall off again. -> Rechecked pressure drop across after-filter-normal. Replaced next downstream filter element (activated carbon element).  This filter didn't look clogged but replaced anyway -> No Help.  Flow seems to be restriced or excessive demand from LVEA.  Output 0.2 psi (normal is > 0.5 psi). -> Double checked point-of-use butterfly valves in LVEA and walked down Class 100 air heade.  Noted that receiver tank which supplies the drying tower stays in nominal 80 -120 psi range and that compressor duty cycle is normal.  In-chamber work taking place and don't want to shut off purge air at this time.  

Will continue trouble shooting when purge air can be shut-down.