ProAir 2200
ENMET
Manual Revision Date – May 3, 2017
P a g e
|
15
Manual Part No. – 80002-046
4.7 Fault Indications
4.7.1 Low Flow Indication
A flow sensor is used to furnish a low flow indication. When the sample air pressure drops below approximately 0.3 LPM, the
fault light and audio alarm are activated, and the display flashes “Low Flow Alarm”.
4.7.2 Other Fault Indications
Other fault indications are associated with sensor zero and calibration activities, and are described in the maintenance
Section
5.0
of this manual.
4.8 Dew Point Sensor Response
It is a characteristic of the
ProAir 2200
that it takes more time to extract moisture from a sample by passing dry air through it, than
it does to add moisture to a sample by passing moist air through it. Therefore, the time response of the instrument to a step change
from moist to dry air is slower, then the response to a step change from dry to moist air.
It is the nature of most materials to absorb and release moisture at different rates. In general, it typically takes longer for a system
to establish moisture equilibrium when going form a high to low humidity than it does to go from low to high. The
ProAir 2200
is
no different. It may take up to 12 hours to establish moisture equilibrium when the instrument is first put on the air line if the Dew
Point is less than 0
°
F. The sensor T90 response time is 10 seconds for a –40
°
to +50
°
F step change and 240 seconds for a +50
°
to
–40
°
F step change. The delivery apparatus such as regulators, piping and tubing account for the additional response time of the
instrument as a system.
4.9 Hydrocarbon Sensor Response
If a Hydrocarbon (HC) sensor is supplied with the
ProAir 2200
instrument, it designed to detect hydrocarbon gases and vapors
with an ionization potential (IP) of 10.6 eV or less. Hydrocarbons with an IP of greater than 10.6 eV will NOT be detected.
Please see Appendix B for a list of common gases and vapors and their respective IP rating.
Unless otherwise noted Isobutylene is used as a calibration and reference gas.
