Beckett CG15, CG50, CG25 manual Verify Input Firing Rate

Section: Start the Burner

B)At burner start-up - Note, as soon as the burner lights, be prepared to adjust the butterfly valve to set the low fire rate adjustment.

1.Monitor the flame through the observation port. If it appears to be too rich (yellow-orange flame), move the butterfly valve shaft slot setting toward a more vertical position. (This adjustment is made by turning the nut holding the spring-loaded swivel on the butterfly valve arm. If insufficient adjustment is available by this method the butterfly valve shaft can be repositioned in the arm. Care must be taken to make only small changes.)

2.Use a flue gas analyzer to check the flue gas ratings for O2 and CO. Your target should be 4% O2 and CO should be well below 50 PPM. (Note that the CO is usually near 0 at 4% O2.)

3.If the O2 and CO levels are not on target, turn the low fire adjustment nut as required to meet the target listed in Step 2.

4.Check the low fire rate. Either clock the meter or compare the manifold pressure drop to factory standards. Adjust the low fire cam setting in the damper motor (if necessary refer to the Initial Air Setting procedure described previously) and the butterfly valve shaft slot position as described in Step 1. Refer to Step 2 in this procedure and double check the O2 and CO readings.

5.When low fire is set, use the modulation controller to manually step the burner up to its high fire rate.

6.Check flue gas O2 and CO. Your target should be 3% O2. CO should be well below 50 PPM, and is usually near 0 for that O2. Adjust the regulated gas pressure as required to meet the target.

7.Check the high fire rate and adjust the high fire cam setting and regulated gas pressure as required to meet the target. (If necessary, refer to the Initial Air Setting procedure described previously.)

8.Using the modulation controller, manually step the burner back down to low fire and verify the O2 and CO ratings. If the high fire adjustments were significant they may have affected the low fire settings as well. Refer to Step 4 in this procedure to make adjustments as necessary.

9.Using the modulation controller, manually step the burner through its range, stopping at several points to check O2 and CO measurements.

10.After you are satisfied with the modulation linkage adjustments secure all linkage fasteners and continue the start-up procedure.

It is acceptable for a burner with linkage control of the fuel to show

2% variation in O2 through the range as long as O2 stays above the target points. If the O2 drops below the target points it may lead to a CO problem. Moving the damper arm position on the damper shaft changes mid-range O2. Loosening the clamping screws and moving the swivel end of the arm downward increases midrange O2, upward decreases it. This change will affect the low fire O2 setting, and you’ll need to re-set it.

Verify Input Firing Rate

1.Clock the meter, correct for pressure and termperature to get SCFH and calculate the input firing rate. Compare the calculated rate to the specified input for the boiler found on the specification sheets and on the rating plates for the burner and boiler. Do not exceed the specified maximum input for the boiler.

2.Attach a manometer to the manifold test port, clock the meter, and adjust the regulated pressure until the specified input level is achieved. Refer to Table 3.

3.Be sure to set the breech or furnace pressure to the correct value, since this will have an effect on the manifold pressure.

CG15, CG25, CG50 Burner Manual

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