53.2.3. ManifoldThe manifold is a central flow-switching chamber, which connects the nebulizer, impactor, vacuumline, drain outlet, and drain reservoir. It is from this chamber that adjustable portions of the aerosolare discarded through the drain and vacuum system while the remainder goes to the final teststream.3.2.4. ImpactorThe impactor, located inside the manifold, consists of a metal disc with 3 small holes. The functionof the impactor is to select the aerosol particulate with proper size distributions (smoke sizedparticles). Do not modify (enlarge or close) any holes on the impactor.3.2.5. Drain Reservoir (Figure 1 (10))In order to control the concentration of aerosol in the test stream, varying amounts of aerosol fromthe nebulizer are pulled by the vacuum into the filter, or by gravity into the drain reservoir. The drainreservoir should be attached to the drain outlet before any testing. In order for the system to work,the drain reservoir should not contain any leakage. The drain reservoir should be emptied when it isabout 3/4 full or before storage.3.2.6. FiltersThe disposable filter (blue) on the front panel absorbs all of the excess smoke from the vacuumstream before it enters the vacuum pump. It protects the mass monitor and the vacuum pump.The filter SHOULD be replaced when the filter element turns red, which is after about 100-150 tests.3.2.7. ControlsFunction Switch (ON/OFF/Battery recharge) The switch should be set at the “OFF” position duringstorage or between tests. When the switch is set at the “ON” position, the blower will beturned on and the system will be ready. To charge the internal battery, connect the NiMHcharger provided and turn the switch to the “Battery recharge” position.Compressor/Pump Switch (ON/OFF) When the system is ready (Function Switch set at the “ON”position), set the Compressor Switch at the “ON” position will turn on the compressor.Concentration of the aerosol can then be adjusted using the Concentration Adjust knob.Dilution Adjust. The dilution LED lights (Red, Green, Yellow) indicates the dilution airflow rate. Thecorrect rate is shown by the green light. Red and yellow mean "high" and "low" respectively.To maintain the correct airflow rate, adjust the dilution knob on the right of the top panel untilthe green light is on. If normal adjustment is not enough, one or a few of the 6 openings inthe diffuser located inside the shroud (the clear plastic bowl) may have to be enlarged orcovered. (See Table 1, Problem Diagnostics, P. 15).Pressure Adjust The pressure LED lights (Red, Green, Yellow) indicates the compressed airpressure. The correct rate is shown by the green light. Red and yellow mean "high" and"low" respectively. To maintain the correct pressure, turn the pressure adjust knob on thetop panel until the green light is on.Concentration Adjust. Use the concentration adjust valve to adjust the sensitivity reading on yourLCD. Turning clockwise will lower the sensitivity readout (smaller amount of smoke output)whereas turning counter-clockwise will increase the sensitivity readout (larger amount ofsmoke output).Internal Battery / External Power Source Switch (for newer Models May 2004 or later only) on the leftpanel. When set at the “INT BAT” internal battery position, the tester will be powered by theinternal NiMH battery. When set at the “EXT Power” position, the tester will be powered byan external power source, either through the provided AC Adapter (12VDC output) or anyother 12V DC battery. The AC Adapter or an external 12VDC battery must be connected tothe “AC Adapter/Ext Battery” jack next to the “INT BAT/EXT Power” switch.