RKI Instruments GD-K8A - Manual (Page 12)

8 • Model GD-K8A Diffusion Detector Head
Maintenance
This section describes maintenance procedures for the GD-K8A. It includes preventive
maintenance and troubleshooting procedures.
Preventive Maintenance
This section describes a preventive maintenance schedule to ensure the optimum
performance of the GD-K8A. It includes daily, monthly, and quarterly procedures.
Daily
Verify a display reading of 0 at the controller. Investigate significant changes in the display
reading.
Monthly
NOTE: Verifying the response of the GD-K8A may cause alarms. Be sure to put the
controller into it’s calibration program or disable external alarms before
verification.
This procedure describes a test to verify that the GD-K8A responds properly to the target
gas.
Preparing for the response test
1. Verify that the display reading for the channel you plan to test is 0.
If the display reading is not 0, set the zero reading of the GD-K8A as described in the
Start Up section of this manual, then continue this procedure.
NOTE: This procedure describes a test using a fixed flow regulator with an on/off knob.
2. Connect the calibration kit sample tubing to the calibration adapter and to the fixed
flow regulator.
3. Open the GD-K8A’s door and attach the calibration adapter over the face of the
sensor.
4. Use small test clips to connect a milliampmeter to the output check pins.
5. Use the following formula to determine the correct GD-K8A response output for the
calibrating sample.
Response Output (mA) = (calibrating gas/fullscale) X 16 + 4
For example, if you have a cylinder of 5 ppm calibration gas with a GD-K8A full scale
of 10 ppm:
12 mA = (5 ppm/10 ppm) X 16 + 4