Super Systems Gold Probe - Manual (Page 7)

6
SSi Gold Probe Manual Rev C
Fig. 5
VALVE CLOSED
VALVE OPEN
millivolts
600
500
400
300
250
200
100
BURNOUT COMPLETE
TIME
Ec
15 MIN
TYPICAL FURNACE BURNOUT
INSTALLATION (CONT’D)
If you already have a control system for your
carbon sensor, you have been provided with a
reference air supply and perhaps a probe
conditioning system as well (see Fig. 6). It is
important to emphasize that the reference air be
clean and dry. Any combustibles or moisture in
the reference air will cause the sensor to read
low, resulting in over-carburization. Avoid the
use of lubricated plant compressed air. Air
connection at the sensor should be silicone
rubber tubing to avoid problems related to the
high temperatures normally encountered at the
sensor connection block.
Your final installation should look similar to that
of Fig. 4.
MAINTENANCE
Furnace conditioning: The destructive effect of
carbon and temperature at high levels is
conceded by manufacturers who normally
instruct in the art of “
gentle burnout ” . SSi
engineers have developed an even gentler
routine that shortens or eliminates the time
required to
“season” the furnace after a burnout
has been completed. The recommended routine
for burnout is to set the temperature to 1500
 F
(815  C), discontinue the carrier gas, and start to
add air at a rate that will not cause a large
increase in temperature. A flow rate of about
10% of the normal flow of carrier gas has been
found adequate. Eventually, the Gold Probe™
output will fall to 200 mV. At this point,
discontinue the air and observe the probe output.
If the output rises above 250 millivolts in less
than 15 minutes, turn the air on and repeat the
routine until the mV level remains below 250 for
more than 15 minutes. Burnoff is complete. See
Fig.5.
Fig. 4