How to Use the Counter
The Models 228 and 229 are designed for easy and
fast operation. We recommend that you experiment
with your counter until you get a feel for how it per-
forms in different environments and conditions. It is
normal for counts to vary sometimes greatly from day
to day depending on changes in ambient air condi-
tions. Keep in mind that you should be looking for
changing trends in particle count levels over time rather
than changes from one sample to the next.
Model 228 for Monitoring Particle Concentration,
The 228 takes a six second sample (one tenth of a
minute) and then displays particles per cubic foot (or
per cubic liter). When you turn the unit on the display
shows a count-down from 6 down to 1 and then dis-
plays particles per cubic foot. This figure is then up-
dated every six seconds until the unit is turned off.
Model 229 for Monitoring Total Counts,
The Model 229 displays the number of counts in one
tenth of a cubic foot of air. It starts counting when the
power is turned on and the display is updated con-
tinuously as particles are detected. The counter will
run for one minute then hold the displayed count until
the unit is turned off. This count represents the num-
ber of particles in one tenth of a cubic foot of air. (0.1cfm
x 1 min.)
Isokinetic Probe
The Isokinetic probe must always be installed when
a sample is being taken. The probe is designed to
provide a representative sample volume based on
the probe diameter and the 0.1cfm flow rate of the
counter.
If the probe becomes contaminated it can be removed
flushed with isopropyl alcohol air dried and rein-
stalled.
Both models include a purge filter which installs in place
of the isoprobe. Particles left in the counter from earlier
samples in a high concentration environment may affect
subsequent counts.
Sensor ight
The sensor light indicates the condition of the sensor. In
normal operation the light should be off. If the sensor
becomes contaminated or the laser diode of the sensor
should fail the sensor light will come on.
Contamination:
When the counter is used in high concentration or uncon-
trolled environments it is possible for the sensor to be-
come contaminated. If this occurs replace the isokinetic
probe with the purge filter. Run the counter until the dis-
play reads 0 counts. This usually clears the contamina-
tion and the sensor light will go out.
If the sensor light does not go out and or the counter does
not display 0 counts with the purge filter installed con-
tact the Technical Support Group at one of the offices
listed on the other side of this manual.
aser Diode Failure:
If the above procedure does not clear the sensor light or
the counter counts 0 particles with the isokinetic probe
in place the laser diode may have failed. Contact Techni-
cal Support.
Battery ight
The "LOW BATTERY" light will come on when the battery
level is not sufficient to maintain the proper flowrate. Once
a month or if there seems to be insufficient run-time on a
fully-charged battery run the counter continuously until
the batteries are completely depleted then fully recharge
overnight.
General Operating Instructions
1) Remove the protective red cap from the sensor inlet tube;
connect the isoprobe.
2) Turn power on. After six seconds the model 228 will be-
gin displaying particle concentration. This display will
update every six seconds. After power on the model 229
will start a 1-minute totalized count. This count will be
held until power is turned off.
3) If the LOW BATTERY light comes on recharge the battery.
a. Fast Charge:
turn power off connect the AC adapter then turn power
on. The light will blink indicating the battery is charg-
ing then go out when the battery is fully charged. The
battery will completely recharge after 6 hours.
b. Slow Charge:
turn power off connect the AC adapter. Battery will re-
charge in 16 hours (light will not be on during recharg-
ing).