What causes black soot buildup on my gas fireplace logs?

Friday, August 10, 2018

Vented gas fireplace logs will usually have a bit of soot on them because it is a factor of the combustion process, but it is not be the norm for a non-vented fireplace. Excessive sooting can be the result, or combination of, any of three different problems:

  1. The ratio of gas and oxygen may need to be adjusted. A rich gas mixture makes the flame more orange and flickering, which is appealing to most fireplace owners, but too much gas will cause the black powdery build up on the logs, and even on the fireplace insert. Propane fireplaces usually create more soot than natural gas burning units. 
  2. If the ceramic logs are positioned incorrectly they disrupt the flow of the flames and deposit soot where the flame crosses the log. Rearranging the logs usually voids the warranty, so avoid moving them once the technician has installed the unit.
  3. Burners that are clogged, or simply worn out, can also contribute to a sooty mess—not only in the firebox, but we have also seen ceilings and walls that need to be repainted due to soot from a malfunctioning fireplace in the room.

   Here’s a few examples of soot buildup shown below. Always call a gas technician to make any repairs, adjustments or cleaning of your gas fireplace.

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Here’s links to a collection of our other blog posts about FIREPLACES AND CHIMNEYS: 

 Is a gas log lighter dangerous?

What is the 3-2-10 rule for masonry chimneys? 

Why is creosote buildup in a chimney dangerous? 

Why does the house have a chimney but no fireplace?

Why is the chimney leaning away from the house? 

How is a factory-built fireplace different from a regular fireplace?

• The fireplace doesn't have a chimney. Is that alright? 

    Visit our FIREPLACES AND CHIMNEYS page for other related blog posts on this subject, or go to the INDEX for a complete listing of all our articles.

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