AERCO KC Series Equipped with C-More version 3.04 - Manual (Page 34)

INITIAL START-UP
4-4
NOTE:
Always go to a percentage of valve position from the same direction, (i.e., 100% to 30% or 30% to 20%).
Whenever going to a valve position from below (i.e., 20% to 30%), first go above 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 inlet air temperature in Table 1.
12. If the measured oxygen level is within the range in Table 1, no adjustment is necessary. Proceed to
step 1 8 .
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.
Table 1
Combustion Oxygen Levels for a 30% Valve Position
Inlet Air
Temp
Oxygen
(+0.2/-1.0)
Carbon
Monoxide
-20°F 7.5 % <50 ppm
0°F 7.3 % <50 ppm
10°F 7.2 % <50 ppm
30°F 6.8 % <50 ppm
50°F 6.4 % <50 ppm
60°F 6.2 % <50 ppm
70°F 6.0 % <50 ppm
80°F 5.8 % <50 ppm
90°F 5.6 % <50 ppm
100°F 5.4 % <50 ppm
DIFFERENTIAL
PRESSURE
REGULATOR
REGULATOR CAP
CAP GASKET
Figure 4.3
Differential Pressure Regulator
14. Use a flat-tip screwdriver to adjust the differential pressure regulator. Turn the screwdriver:
• counterclockwise to increase the oxygen level
• clockwise to decrease the oxygen level