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TABLE 19. HIGH FIRE RATE
TABLE 20. LOW FIRE RATE
HIGH FIRING RATE SETTING
Set the boiler to the high ring rate by setting the High Firing Rate RPM as described below. Check combustion readings using a
combustion analyzer. If combustion readings are not in accordance with the chart below adjust the gas valve as follows: remove the
at, round, blue plastic cap from the cover. Using a 3 mm (7/64”) hex wrench, turn the adjustment screw counterclockwise to increase
or clockwise to decrease gas ow and achieve the desired CO
2
level. Refer to the Table 19 for correct settings. There will be a slight
time delay between the adjustment and the response of the CO
2
measuring instrument. Adjust the settings in small increments and
allow the combustion readings to stabilize before readjusting. When desired adjustments are complete, reinstall the blue plastic cap
on the cover. Combustion samples should be taken in the stack within two feet of the boiler. The carbon monoxide (CO) values in
the combustion sample should not exceed 150 PPM under any circumstances. Contact OEM for any abnormal conditions leading to
excessive CO above 150 PPM.
MODELS (XB/XW)
RPM
(APPROXIMATE FACTORY SET)
CO
2
*MANIFOLD PRESSURE
INCHES W.C
NATURAL
GAS
PROPANE NATURAL
GAS
PROPANE NATURAL GAS PROPANE
1000 (920,000) 4450 4750 8.5 - 9.2% 9.3 - 10.2% -3.5 -4.7
1300 4850 5100 8.5 - 9.2% 9.3 - 10.2% -3.0 -3.6
1700 5700 5700 8.5 - 9.2% 9.3 - 10.2% -3.6 -4.4
2000 4700 4750 8.5 - 9.2% 9.3 - 10.2% -3.9 -4.9
2600 5700 5100 8.5 - 9.2% 9.3 - 10.2% -3.3 -3.6
3400 5700 5700 8.5 - 9.2% 9.3 - 10.2% -3.5 -4.4
LOW FIRING RATE SETTING
Set the boiler to the low ring rate by setting the Low Firing Rate RPM as described below. Check combustion readings using a
combustion analyzer. If combustion readings are not in accordance with the chart shown below adjust as follows: remove the cap
on the gas regulator using a slotted screwdriver. This will expose the offset adjustment screw. Using a TORX
®
T40 or a 5 mm hex
wrench, carefully adjust the low re gas setting to achieve the CO
2
level prescribed in Table 20.
Note: The rotation of the Low Fire adjustment is opposite of the High Fire as follows: Clockwise rotation increases gas ow,
counterclockwise rotation decreases gas ow.
Adjustments to the offset pressure regulators should not exceed 1/4 turn at a time before allowing the readings to respond and
stabilize.
After proper low re offset adjustment is made, reinstall the slotted cap on the regulator.
Following all gas valve adjustments, check for proper light-off and verify correct fuel/air mix and combustion quality throughout the
entire ring range (from lowest to highest fan speed).
Note: Make sure the Manual Mode is set back to Automatic Mode to each of the burners, once the required settings are
done. Turn off the individual burner before proceeding to the next burner settings.
MODELS (XB/XW)
RPM
(APPROXIMATE FACTORY SET)
CO
2
*MANIFOLD PRESSURE
INCHES W.C
NATURAL
GAS
PROPANE NATURAL
GAS
PROPANE NATURAL GAS PROPANE
1000 (920,000) 1650 1540 7.3 - 8.2% 8.4 - 8.8% -0.3 -0.25
1300 1650 1600 7.3 - 8.2% 8.4 - 8.8% -0.2 -0.14
1700 1700 1700 7.3 - 8.2% 8.4 - 8.8% -0.2 -0.23
2000 1550 1540 7.3 - 8.2% 8.4 - 8.8% -0.3 -0.31
2600 1700 1600 7.3 - 8.2% 8.4 - 8.8% -0.2 -0.14
3400 1700 1700 7.3 - 8.2% 8.4 - 8.8% -0.2 -0.23
* NOTE: Values listed in Table 19 and Table 20 are tested under laboratory conditions with minimum vent length. Values may slightly vary depending on
ambient conditions and eld equipment accuracy.