Zero Adjustment - Hach astroTOC UV 4195-1010 Manuel D'utilisation

Zero gas can be the carrier gas. Connect the zero and span gases directly to the IR manifold.
Calibrate the IR gas when the IR is out of calibration. Make sure that the feed pressure at the carrier
gas inlet is 40-90 psig.
1. In the Service/Elevation menu, set the elevation to 1 m.
2. In the Service menu, push the up arrow three times.
The display shows the IR cal screen.
3. Make sure that the temperature of the IR cell is in the range of 48 to 51 °C. Apply the zero gas
directly to the cell. Let the gas flow for 10 minutes at 200 cc/minute.
4. Identify the IR span gas concentration (1000 ppm or 10000 ppm CO
1000 ppm, LK1 must be out. If the span gas is 10000 ppm CO
Figure 19 on page 37.

Zero adjustment

Make the zero adjustment on the 8000 display/controller board. Refer to
1. Turn the screw clockwise to increase the voltage. Turn the screw counterclockwise to decrease
the voltage. Refer to
2. When the zero gas reading is stable, adjust the Zero potentiometer so that the voltage is between
0.26 and 0.27 V.
0.27 V gives a CO
gas ppm reading on the display could be zero or below zero. The slight increment above zero
makes sure that the gas ppm reading is in a positive range.
36 English
Figure 19.
ppm reading slightly above zero. 0.25 V gives a zero reading, but the actual
2
). If the span gas is
2
, LK1 must be in. Refer to
2
Figure 1 on page 6.