Section: Start the Burner
Optional Modulation Linkage Adjustment Instructions
Figure 12 - Modulation Assembly for Left Handed Gas Entry (Standard Construction)
The optional modulation linkage assembly has been designed as an economic means to adjust the damper and the butterfly valve to maintain air to gas ratios. When the optional Modulation linkage assembly is supplied with the burner, initial adjustments will be made at the factory. To ensure optimum operation, minor additional adjustments must be made after the burner is fired on a boiler.
The following adjustment will be
○The damper motor high fire and low fire cams will be preset.
○The linkage between the damper and the butterfly valve will be preset as illustrated in the manual.
○The butterfly valve shaft will be set to a nominal position.
Figure 11 - Modulation Assembly for Right Handed
Gas Entry (Optional Construction)
Adjustment Procedure
Referring to the appliance manufacturer’s literature, insure that
all preliminary adjustments and calibrations required for the burner and appliance have been performed.
A) Prior to starting the burner
1. Verify that the damper motor high fire and low fire cam settings match the nameplate (Figure 1) or Table 3.
2. Examine the linkage for signs of damage.
3. Referring to the illustrations in Figures 11 or 12, verify that the linkage is installed as shown.
4. Prior to adjusting the burner, have available all the necessary test equipment.
○ A manometer to check pressures downstream of the gas pressure regulator; at the manifold pressure test connection and in the furnace
○ A draft gauge to check breaching pressure ○ A flue gas analyzer that can measure O2 (or
CO2) and CO.
5. Adjust the gas pressure regulator to about ½” WC higher than the anticipated high fire gas pressure (see Table 3).
6. To prevent the burner from modulating to high fire, set the modulation controller to the manual control mode. If necessary, refer to the manual supplied with the modulation controller.
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