INFICON MicroFID II Portable Flame Ionization Detector - Manual (Page 76)

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3. Replace the filter housing.
4. Calibrate all Cal Memories that you are using before continuing operation.
NOTE: Do not operate the MicroFID II without an inlet filter.
Replacing the Sintered Filter (Exhaust Filter)
Through normal use of the MicroFID II, the exhaust frit and cap (Part No. A3201116) can
become clogged with fine carbon ash from continuous burning of vapors and gases which exit
from the detector. It is vital that this piece be replaced often and a supply should be kept on
hand. One of the principle reasons this part needs to be changed out is from excess humidity in
the air while the unit is being used. Excess water saturation of the filter element can cause the
element to trap and bind particulates from the burn process more easily and accelerate the
clogging process. It is suggested that the filter be changed at least once a month to maintain
data and machine integrity if sampling is done in a hot and humid condition or when sampling
high concentrations of organic vapors and gases. If the use of the MicroFID II is infrequent, the
filter can be changed once every six months.
1. Turn off the unit power and close the hydrogen valve.
2. Locate the exhaust frit and cap on the main unit , identified as “Exhaust”. (See
Figure 34)
3. Use the multi-tool to unscrew the old exhaust element counterclockwise and replace
the exhaust element with a new one (Part No. A3201116).
4. The old exhaust frit and cap can be cleaned and reused. Use methanol or alcohol in
an ultrasonic bath.
Calibration
Daily Calibration
The MicroFID II should be calibrated on a daily basis before use.
It is necessary to calibrate the MicroFID II at the temperature at which the unit will be used to
minimize the effects of vapor pressure changes with temperature. Performing calibration at the
same temperature allows the calibration gas and the sample gas to have equal ionization in the
detector.
Monthly Quality Check
Calibration of the MicroFID II as a routine maintenance activity should include measuring the
machine against a known standard of good quality gas, and then comparing the result before
the calibration. This quality check is most commonly known as a "bump test" and helps define
the unit linearity and whether cleaning of the detector collector electrode is necessary. The
unit
’s performance should be within 20% of the calibration level used. This should be performed
once a month and recorded to verify if any changes in the quality check have changed and if the
unit should be sent in for service.