INITIAL START-UP
4-6
5. Set the unit to the Manual Mode by pressing
the
AUTO/MAN
switch. A flashing
Manual
Valve Position
message will be displayed
with the present position in % open. Also,
the
MANUAL
LED will light.
NOTE:
For a review of the control panel operating
procedures
,
refer to Section 3.
6. Adjust the valve position to 0% by pressing
the
▼
arrow key.
7. Set the
ON/OFF
switch to the
ON
position.
8. Change the valve position to 25% using the
▲
arrow key. This will put the unit into the
starting sequence.
NOTE:
On initial start-up, or return to service from a
fault condition, the unit will remain at a 29%
valve position for two-minutes.
9. Following the warm-up period, increase the
valve position in 20% increments while
monitoring the gas pressure after every
increase. If gas pressure dips below 7.7”
W.C. for FM gas trains and 8.1” for IRI gas
trains at any input valve position percentage,
stop and raise the pressure. Once 100% is
reached, adjust the gas pressure for 7.7”
(FM) W.C. or 8.1” W.C. (IRI).
NOTE:
If 7.7” W.C. for FM gas trains or 8.1” W.C. for IRI
gas trains cannot be obtained at the 100% valve
position, it will be necessary to stop calibration
and contact the local AERCO representative in
your area. Running the unit on insufficient gas
pressure will void the warranty
10. Once 7.7” W.C. or 8.1” W.C. is set at the
100% level, change the valve position to
30%. Insert the combustion analyzer probe
into the stack.
NOTE:
Always approach a valve position percentage
from the same direction, (i.e., 100% to 30%,
30% to 20%, etc.). Whenever going to an
increased valve position from below (i.e., 20% to
30%), first go above and then back down to the
desired valve position. This is necessary due to
hysteresis in the air/fuel stepper motor.
Hysteresis causes the air/fuel valve to stop in a
slightly different position if the valve position
percentage is approached from below or above.
This results in a difference in oxygen readings
for the same valve position percentage causing
unnecessary recalibration
.
11. Allow enough time for the combustion
analyzer to settle. Compare the measured
oxygen level to the oxygen range for intake
air temperature in Table 4. Also, ensure that
the carbon monoxide (CO) and nitrogen
oxide (NOx) readings do not exceed the
values shown.
Table 4
Combustion Oxygen Levels for a 30%
Valve Position
Inlet Air
Temp
Oxygen
(±0.2%)
Carbon
Monoxide
*NOx
-25°F
7.8%
<100 ppm
<30 ppm
-10°F
7.5%
<100 ppm
<30 ppm
0°F
7.4%
<100 ppm
<30 ppm
10°F
7.2%
<100 ppm
<30 ppm
25°F
6.9%
<100 ppm
<30 ppm
40°F
6.5%
<100 ppm
<30 ppm
55°F
6.4%
<100 ppm
<30 ppm
70°F
6.2%
<100 ppm
<30 ppm
85°F
5.9%
<100 ppm
<30 ppm
100°F
5.7%
<100 ppm
N/A
* NOx readings corrected to 3% oxygen.
12. If the measured oxygen level, CO and NOx
emissions are within the ranges shown in
Table 4, no adjustment is necessary.
Proceed to step 19.
13. If the measured oxygen level is
not
within
the range listed in Table 1, remove the
regulator cap and cap gasket from the
differential pressure regulator (see
Figure 4.3) and proceed to step 14.
