RKI Instruments GD-K7D2 (24 VDC) - Manual (Page 21)

Model GD-K7D2 (24 VDC) Sample Draw Transmitter • 17
Storing the GD-K7D2
The GD-K7D2 has a circuit on the main board that keeps a bias voltage on the gas sensor
whenever there is no incoming power, such as during shipment, storage, or power
outages. This circuit is powered by the lithium battery pack. If the lithium battery pack is
dead when power to the GD-K7D2 is turned off or is lost, then the bias voltage normally
on the sensor during operation will not be applied to the sensor. If the sensor is without
the bias voltage for an extended period, it will take some time to stabilize and be ready for
use after power is restored. If the sensor is off bias for too long, it may not be usable when
power is restored.
The lithium battery pack will last approximately three years if the GD-K7D2 is on power
all the time, approximately 2 years if it is on power for eight hours a day, and
approximately 18 months if it is always off power. Be sure to replace the battery pack
periodically to assure that the sensor will always be on bias during power outages.
If the GD-K7D2 is going to be stored, make sure a fresh battery pack is installed to
maintain a bias on the sensor. See the next section for instructions to change the battery
pack.
In addition to keeping the sensor on bias during storage, it must be kept upright. If the
GD-K7D2 is stored, it must be oriented so that the sensor is upright.
WARNING: If the GD-K7D2 is not stored in an upright position, the sensor membrane
which allows gas into the sensor may dry out and the sensor may not
recover proper operation.
Replacing Components of the GD-K7D2
Replacing the Fuse
1. Turn off the controller.
2. Turn off power to the controller.
3. If providing 24 VDC to the GD-K7D2 from a source other than the controller, turn off
the power source.
4. Place the GD-K7D2’s ON/OFF switch in the OFF position.
5. Unscrew the captive thumbscrew on the cover and remove the cover.
6. Remove the four flat head screws on the top of the detection unit that hold down the
metal cover over the main board.
7. Remove the old fuse from the fuse clips and replace it with the new one. See the parts
list for the RKI part number for a replacement fuse.
8. Reinstall the metal main board cover with the four screws.
9. Reinstall the GD-K7D2 cover.
10. Turn on power to the controller and turn on the controller.
11. If providing 24 VDC to the GD-K7D2 from a source other than the controller, turn on
the power source.
12. Place the ON/OFF switch in the ON position.
Replacing the Sensor
1. Turn off the controller.
2. Turn off power to the controller.