Soot build up - natural gas fireplace

[e2tango]

Well bit stumped on what's causing this. Fireplace is in a home that's maybe 6 years old. Just recently started having a lot of black soot build up on the logs. It even showed up outside on the siding above where it vents out.

Had HVAC guy over as the fireplace stopped working. He replaced the thermocoupler and said all was well. It's working still but keeps building up a piles of soot on a specific area on the log ( I where else) . I've vacuumed all the area out. Verified location of logs is correct and still returns.

Took some pictures here. Been reading online and could it be an air / fuel mixture causing this? How do I adjust that?

 

[jsiets]

With just a quick look at the photos it appears to be a impingement issue log off a little bit and blocking flame a little bit to much or on of those ember chunks blocking a burner port

 

[DAKSY]

Well bit stumped on what's causing this. Fireplace is in a home that's maybe 6 years old. Just recently started having a lot of black soot build up on the logs. It even showed up outside on the siding above where it vents out.

Had HVAC guy over as the fireplace stopped working. He replaced the thermocoupler and said all was well. It's working still but keeps building up a piles of soot on a specific area on the log ( I where else) . I've vacuumed all the area out. Verified location of logs is correct and still returns.

Took some pictures here. Been reading online and could it be an air / fuel mixture causing this? How do I adjust that?

What manufacturer & model do you have?
Generally, the appearance of soot , especially on the outside of your home is an ATF mixture setting.
The manual should tell you how to do that. Look under "Aeration," or "Air Shutter Setting."