Q: Filters – What is a carbon filter and why do I need one?
A: A carbon (or charcoal) filter reduces the quantity of non-methane hydrocarbons in the gas stream, which ensures a more accurate methane level reading.
Q: Filters – What is a water trap and why do I need one?
A: The water trap is a filter that removes moisture from the gas stream. If you get liquid droplets in your gas sample, the water trap will prevent them from going into the body of your instrument. Otherwise, the GEM could suffer serious damage. If you are using a charcoal absorber filter, the water trap should come before the charcoal absorber. That is, the charcoal filter should be closer to the instrument.
Q: Filters – What is a particulate filter and why do I need one?
A: A particulate filter removes small particles—dust, pollen and so forth—from the gas stream. This is important because particles degrade the instrument’s performance and must eventually be cleaned out during servicing. The particulate filter is inside the GEM-2000 body, in the back behind the circular door with the large slot in it. The door can be opened with a quarter or something similar. Slide the quarter into the slot and turn counter clockwise. The particulate filter should be checked regularly, at least every three months, and replaced immediately if it is clogged.