11
A100g
JULY 2017
CALIBRATION OF SENSORS
FIG. 12
HORN
S
Z
1 2 34 5 6 7 8
ELECTRO CHEMICAL BOARD SHOWN
(SEMI CONDUCTOR IS SIMILAR)
ZERO POT
ADJUSTMENT
SPAN POT
ADJUSTMENT
SENSING
ELEMENT
0-5V DC
FIG C
O V
V S
REGULATING
VALVE
CALIBRATION GAS
3100-13
BOOT
SENSING ELEMENT REPLACEMENT
Basic Sensors
The Basic Gas Sensor uses a three pin plug-in element
for Ammonia Sensors and six pin plug-in element for
Halocarbon Sensors which is internally mounted to
the circuit board. To replace, disconnect power and
open the enclosure. The sensing element is removed
by hand; lifting it off the circuit board. Install the new
sensor element by lining up the pins and press firmly into
place. Connect power and allow the sensor element to
stabilize for 24 hours. Recalibrate and install the cover.
Standard, Harsh and Explosion Proof Sensors
Standard, Harsh and Explosion Proof Sensing Elements
are externally mounted to the enclosure. To replace,
disconnect power, open enclosure and disconnect cable
wire from the circuit board. Unscrew sensor element
from enclosure. Install new sensor element. Connect
power and allow sensor element to stabilize for 24 hours.
Recalibrate and install the cover.
Extreme Sensors
Extreme Sensing Elements are internally mounted to
the enclosure. To replace, disconnect power, remove
nut and gasket from sensing element at the base of the
unit, open enclosure and disconnect cable wire from the
circuit board. Remove sensor element from enclosure.
Install new sensor element in reverse order. Connect
power and allow sensor element to stabilize for 24 hours.
Recalibrate and install the cover.
Note:
After replacing sensing element recalibration of
sensor is required.
Note:
Infrared sensing element (CO
2
) is not replaceable
Note:
For 250 PPM sensors only, special kits are
available which include both the new circuit board and
appropriate 250 PPM sensing element. Refer to page
24 for special replacement kits.
