Purpose of air shutters.

[thermodynamix]

I understand air shutters control the flow of air to the burner. Open = more air, closed = less air. Typically people open the shutter when their flames are yellow, which can cause soot.

Why not just open the air shutter all the way? Wouldn't that be ideal for soot prevention?

 

[Lennox65]

Technically, yes. But part of the appeal of gas fireplaces is the aesthetics. In most cases, a fully opened air shutter will result in a small blue flame which is not visually pleasing. Closing the air shutter "dirties " up the flame and makes it look more like a wood fire with taller yellow tips on the flames. You should start with the manufacturers recommended opening.

 

[DAKSY]

The air shutter regulates the Air-to-Fuel mixture.
Yellow flames do not necessarily result in sooting.
Orange flames with black tips will cause soot.
Ideally, your flames should be blue near the burner
ports & yellow at the top.