Delta OHM HD35AP series, Operating Manual

Page: 56 / 146

HD35
- 56 -
V1.12
Calibration procedure:
1.
Place the instrument in clean air or connect the nitrogen bottle as indicated above.
2. Wait for at least 15 minutes for the measurement to stabilize, with the instrument on.
3. Access the menu with the administrator password and select the item Calibration ⇒ CO 0
ppm calibration. Press ENTER to confirm.
CALIBRATION
1) CO 0 ppm calibration
2) CO sensitivity calib.
3) CO
2
Calibration
4) Calibration Type
5) Exit

select <ENTER>confirm
4. Select the option OK and confirm with ENTER: the instrument stores the calibration
and returns to the calibration submenu.
CO 0 ppm CALIBRATION
Calibrate CO 0 ppm
measure
Meas. [ppm] Cal. [ppm]
1 0
OK . CANCEL

select <ENTER>confirm
5. If the nitrogen bottle was used, close the bottle tap, remove the CO sensor sleeve and
place again the protection grid by fixing it with the two screws.
8.6.2 R
EPLACING THE
CO
SENSOR
The CO sensor has an expected average life of over 5 years of use in normal conditions. Where
it becomes necessary to replace the CO sensor, proceed as shown below.
Replacement procedure:
1.
Unscrew the two front screws on the housing, remove the back cover and disconnect the
battery.
2. Unscrew the two screws fixing the protection grid of the sensors, remove the grid and ex-
tract the exhaust CO sensor (see fig. 8.6.1 for sensor position).
3. Take the new CO sensor and note the number marked on the edge of the new sensor indi-
cating its sensitivity in nA/ppm.
Fig. 8.6.2: CO sensor sensitivity
4. Insert the new sensor electrodes in the contacts.
5. Apply again the protection grid by fixing it with the two screws.
6. Reconnect the battery and close again the housing by fixing the 4 front screws.
7. Access the menu with the administrator password and select the Calibration ⇒ CO sensitivity
calib. item. Press ENTER to confirm.
Sensitivity