6-2
Airnet® II 4-Channel Particle Sensors Operations Manual
Chapter 6
: Troubleshooting
Airflow Rate Errors
Airflow Rate Errors
As a result of the performance check procedure (see
Performance Checks), the flow rate at the sensor’s inlet should be the following:
•
0.1 CFM for models 201-4, 301-4, 501-4: 0.085 - 0.115 CFM (± 5 %)
•
1.0 CFM for models 310-4, 510-4: 0.85 -1.15 CFM (± 5 %)
A flow rate error greater than 15 % (±5%) indicates that maintenance is required.
Low flow could be due to an obstructed orifice, leaks or insufficient vacuum.
A minimum of 12 inches of Hg vacuum is required at the Airnet II 4-Channel particle
sensor’s critical orifice to provide the required sample flow rate. If the flow rate is still
low after determining that there is sufficient vacuum, perform the following
procedure.
Isolating and Repairing Leaks
To isolate and repair leaks:
1.
Remove the top and bottom halves of the instrument.
2.
Run samples.
3.
While a sample is running, use a bulb syringe to blow a small amount of smoke
around the possible leak paths and watch for an increase in the number of
counts.
The following locations are possible leak paths:
•
Where the inlet jet meets the body of the sample block
•
Around the laser diode
•
Around the photodiode
•
Around the laser window
•
Around the beam dump
•
Around the mirror plug
4.
If a leak is suspected around the inlet jet, remove the jet and O-ring, clean
lubricate and/or replace parts.
5.
Reassemble the unit.
6.
If a leak is suspected around the laser diode or photodiode, contact Particle
Measuring Systems for assistance.
