Bacharach PCA 2 24-9448 - Manual (Page 88)

Instruction 24-9448 6-8
Maintenance
6.4 Sensor Only Replacement
All sensors are replaced n a smlar manner. Do the followng to
replace ether the O2, CO-LO, CO-HI, NO, NO2, or SO2 sensor. Refer
to Section 8.1 Replacement Parts for list of sensors and part numbers.
Turn OFF the analyzer.
Remove the battery cover.
Remove the sensor retaner.
Remove the tubng from the gas cup of sensor beng replaced.
Unplug the sensor along wth ts prnted crcut board from the analyz-
er’s man board.
Remove the sensor’s gas cup by twstng ts bayonet fttng counter-
clockwse, and then pullng the cup straght up.
Carefully remove the old sensor from the Smart sensor PCB, keepng
n mnd that there s an adhesve foam dsk n between the PCB and
sensor. Gently remove any adhesve from from the PCB.
Important! When replacing the O2 sensor, be sure that the “+” sensor
pin plugs into the PCB socket that is also marked “O2+”.
When replacing an NO sensor, also replace the bias battery.
9. Remove the replacement sensor from ts plastc canster. Note that
the CO-LO, CO-HI, SO2,
and NO2 sensors have a
shortng-sprng nstalled
between two of ther pns.
Remove and dscard ths
sprng before nstallng the
sensor.
10. Place the adhesve dsk on
the bottom of the new sen-
sor and plug the new sen-
sor nto the sensor PCB.
11. Attach the gas cup to new
sensor, makng sure that
when the sensor assembly
s plugged nto the analyz-
er’s man board, the tubng
connectons on top of gas
cup are algned as shown
n Fgure 6-3 on page 6-4.
1.
2.
3.
4.
5.
6.
7.
8.
Gas Cup
Sensor Retainer
Sensor
Twist gas cap
bayonet fitting
counterclockwise
to release
Sensor electrical
connector mates with
pins on analyzer’s main
board
Printed
Circuit Board
Adhesive
foam
disk
Be sure to remove any
shorting spring from the
new sensor pins before
installing! There is no
shorting spring on the
O2 or NO sensors.