H. Maintaining and Troubleshooting the AQSync
Model AQSync Air Quality Monitoring Station Manual Rev. A-1
52
H.2.4
CO
2
Module Troubleshooting
When sampling ambient air, CO
2
readings of less than 400 ppm indicate a problem with
the autozero operation, such as the zero gas not being connected, the CO
2
absorber
being exhausted, or the zero valve not operating properly.
The pump for the AQSync’s ozone module is used to provide the air sample to the CO
2
module (as well as the CO module and optional VOCs module). The flow rate through
the CO
2
/CO/VOCs modules is ~100 cc/min. If the ozone module’s pump were to fail,
the measurements for the CO
2
/CO/VOCs modules will be affected. See the discussion
in Section H.2.2 regarding diagnosis of pump failure in the ozone module.
The CO2 Parameters screen
should have values of
approximately:
•
55°C for the temperatures of
the IRGA thermostats.
•
Pressure close to ambient
pressure
•
Current AD values ~55,000
•
Zero AD values greater than
current AD values (say,
60,000)
The AD values are diagnostic of the lamp and detector status. Declining or zero values
would indicate an aging detector and/or lamp. The manufacturer states that the infrared
source should last for at least 2 years depending on use.
Erratic values could indicate a dirty inlet filter. Replace the green inlet filter quarterly,
or more often if sampling very dirty air.
H.2.5
PM Module Troubleshooting
A filter placed before the pump keeps contaminates from damaging the pump, and filters
the air supplied for the air sheath. The flow rate shown on the Particle Parameters
screen should read 1.0 ± 0.1 liters per minute. Changes from this flow rate will make
the particles appear to be larger or smaller. For highest data quality, it is advisable to
regularly monitor the flow rate.
If the flow rate drops below 1.0 ± 0.1 liters per minute, it is possible that the filter has
become dirty and needs to be replaced. As noted in the Maintenance section of this
manual, it is best practice to replace the filter at least quarterly. Deviations in the flow
rate could also indicate malfunction of the module’s pump or the flow meter.
60165
56122
419 ppm
55.7 C
56.1 C
58.3 C
927 mbar
