Burner Adjustments

LENNOX HEARTH PRODUCTS • MONTEBELLO® SEE-THROUGH DIRECT-VENT GAS FIREPLACES (LSM40ST-N / LSM40ST-P) • CARE AND OPERATION INSTRUCTIONS

(QUALIFIED TECHNICIANS ONLY)

Flame Appearance and Sooting

Proper flame appearance is a flame that is blue at the base and becomes yellowish-orange in the body of the flame. When the appliance is first lit, the entire flame may be blue and will gradually turn yellowish-orange during the first 30 minutes of operation. After 30 minutes of operation, if the flame is blue, or if the flame is orange with evidence of sooting (black tip), the air shutter opening may need to be adjusted.

If the air shutter opening is closed too far, sooting may develop. Sooting is indicated by black puffs developing at the tips of very long orange flames. Sooting results in black deposits forming on the logs, appliance inside surfaces and on exterior surfaces adjacent to the vent termination.

Sooting is caused by incomplete combustion in the flames and lack of combustion air enter- ing the air shutter opening. To achieve a warm yellowish-orange flame with an orange body that does not soot, the shutter opening must be adjusted between these two extremes.

Burner Air Shutter Adjustment

Guidelines

•If there is smoke or soot present, first check the log set positioning to ensure that the flames are not impinging on any of the logs. If the log set is properly positioned and a sooting condition still exists, then the air shutter opening should be increased.

•The more offsets in the vent system, the larger the air shutter opening will need to be.

•An appliance operated with the air shutter opened too far, may have flames that appear blue and transparent. These weak, blue and transparent flames are termed anemic.

•Propane models may exhibit flames which candle or appear stringy. If this is present and persists, adjust the air shutter to a more OPEN position, then operate the appliance for a few more minutes to ensure that the flame normalizes and the flames do not appear sooty.

The following chart is provided to aid you in achieving the correct air shutter adjustment for your installation.

Air Shutter Adjustment Guidelines:

Amount of	Flame	Air Shutter
Primary Air	Color	Adjustment
If air shutter is	Flame will	Air shutter
closed too far	be orange	gap should be
		increased

If air shutter is	Flame will	Air shutter
open too far	be blue	gap should be
		decreased

Volcanic Stone

Air Shutter Adjustment Lever

Burner Flame Appearance

(Control Side)

Figure 20

Volcanic Stone

Burner Flame Appearance

(Opposite Control Side)

Figure 21

NOTE: DIAGRAMS & ILLUSTRATIONS ARE NOT TO SCALE.