Teledyne PEM-9004 - Portable emissions analyzer - Manual (Page 23)

Portable Emissions Monitor Operational Theory
Teledyne Analytical Instruments 11
CONNECTED TO THE GAS OUT PORT AND VENTED
PROPERLY.
USE CAUTION WHEN CHANGING FILTER
ELEMENTS OR OTHERWISE OPENING ANY
PORTION OF THE SAMPLE SYSTEM. ALWAYS
PURGE THE SAMPLE SYSTEM TO REMOVE ANY
TOXIC OR FLAMMABLE GAS FROM THE LINES
BEFORE PERFORMING ANY MAINTENANCE ON
THIS INSTRUMENT.