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Troubleshooting Your FP-25
Issue: Volumetric flow readings don't match another flow calibrator I use.
Action:
The FP-25 is the first flow calibrator to account for the content of
water vapor in the air (relative humidity). The live humidity sensor
keeps up with changing humidity levels all the way to 100% RH.
The higher the humidity, the more deviation you may see when
comparing FP-25 flow readings to uncompensated flow instruments.
When the air is dry, differences in flow readings are likely the result of
pressure drop. Every flow meter has some amount of pressure drop,
especially those that use differential pressure as the measurement
method. Differing amounts of pressure drop can result in different
flow readings when used with samplers that do not actively control
their pumps to maintain their target flow rates. This difference is most
noticeable when the FP-25 is mounted in Direct Mode, since the barb
fittings attached to flow audit adapters act to restrict flow rates.
Issue: Mass flow readings don't match another flow calibrator I use.
Action:
Check the STP or NTP settings (MENU > SETUP > BASIC CONFIG > STP/NTP) to
ensure that your standardized temperature and pressure references
match those of your other flow calibrator.
Issue: My flow readings won't change when flow changes.
Action:
If your flow readings are fixed near 0 or 25 lpm and won't change
regardless of actual flow, your flow sensor may be damaged. Please
contact Alicat to troubleshoot the issue.
Issue: Can I use the Alicat with other gases?
Action:
No, the FP-25 is designed specifically to work with ambient air at
any humidity level, 0-100% RH. If you need a flow calibrator to use
with other gases (like CO, CO
2
, NO
x/y
or SO
2
), ask us about our MWB
"Whisper" series, or visit
.
Humidity Readings
Issue: Can I use the Alicat in 100% humidity? Even when it is hot?
Action:
Yes! The FP-25 is the first flow calibrator to be just as accurate in
a Miami summer as it is here in Arizona. The live humidity sensor
keeps flow readings accurate from 0% RH to 100% RH, even at 60°C.
However, take care that moisture is not condensing inside the flow
path, as this will negatively affect its measurement accuracy.
Issue: Can I use the humidity readings for EPA reporting?
Action:
No. The accuracy of the humidity sensor is 3.5% RH, which falls below
the 2% accuracy that the EPA requires.