Thread: White residue on gas fireplaces

Can anyone tell me what causes the white staining condition seen in the attached picture. Also this unit had no blower fan installed, do these units require a fan??

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The white residue is a product of natural gas combustion. When the unit first lights, the glass is cool enough to allow moisture from the combustion process to condense on the glass. As the glass surface heats up, the moisture subsequently evaporates but leaves the residue behind.

There is no requirement for a fan to be on the unit and it should gravity vent on its own if properly installed. Based on your photo though, I would say that the fireplace unit is not venting properly for some reason.

The white residue is a withes brew of several things. As Phil noted, any gas appliance will make some of this haze. However, silicone is notorious for ruining glass. based on the info. given and pic I would recommend a tech service the unit to see why it is getting this buildup along with some soot on the glass. Usually, you find logs out of position, too much ember material and a huge glob of silicone where the thermopile was replaced.

Fan is optional per the listing. IF it was required, would be interlocked.
HTH

Bob and Phil,

Why, sometimes, does this happen, but all clears up within a few minutes? I did a house a few months ago that had two units. Both did this after burning about 3 -5 minutes. No visible residue was present once the fog cleared. The units were about five years old. I did recommend tech service to assure proper combustion and exhaust.

You're confusing the fog that burns off on every sealed unit as opposed to a permanent residue.

There has been much rumor as to the makeup of this white residue including acids, minerals and as I said silicone. While working for a mfr, we had it analyzed and it is all the abovel.

There are now several products on the market made specifically to remove this residue. The most common is called "White Off" made by Rutland. You can use a variety of cleaners from ceramic glass cleaners such as Cerama-Brite to metal polishes such as Brasso or Noxon, which have been tested by Heatilator. This crud must be ground off with a micro abrasive so, like valve grinding compound or metal polish, that is what they do.

Thanks.

I'm seeing more of the LCD "fireplaces" at home shows. I've seen none installed yet. They're pretty Impressive and make a lot more sense in South Texas.

Looks to be about 14" hearth extension, which would not pass for solid fuel but is ok for that gas insert.

I see soot tracks inside the Fp on the glass.