New home...gas logs vented or not?

[newguy09]

We just moved into a new home. Gas logs have been installed in what was a regular fireplace at one time. I can't find a model number on them nor was the manual left. I am trying to determine if they are vented or vent free. Also I would be happy to hear any tips as this is the first time I've owned a gas burner.

Here is what I know:
There was a receipt in with a box of manuals that was left. It was purchased new from Lowes in 2000 for 259$ and was installed by the local propane company.

There are 3 logs in it. 2 big ones that run left to right on bottom and a smaller one that runs front to back on top of them. These were all able to be moved but you could tell they were designed to sit a certain way.

There is an igniter on the left and on the right the knob has settings of off, pilot, and on (with adjustable levels). When on the flames are fairly large.

I can take pic tomorrow if needed.

 

[DAKSY]

Probably gonna need a pic. If we could see the pilot hood, we can tell. An unvented gas log usually has pilot that is narrow & noisy & looks like a small rocket motor concentrated on the sensors (thermopile(s) & or thermocouple). Most vented gas logs have a lazy pilot that doesn't make a lot of noise, but YMMV...

 

[webbie]

If the flames are fairly large and yellow and there is lots of soot on the logs, chances are it's vented......

But if there is a lot of blue in the flame before the flame contacts the logs.....may be unvented.

Chances are that there is a tag affixed to it somewhere...or a pic would be good.
Another hint is that most unvented would have embers spread on top of the burner, while most unvented would have a bare burner.

 

[newguy09]

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(broken image removed)

 

[webbie]

My first take is unvented due to the burner being well above the bottom and having precision slots in it.

BUT, it's very possible that this will never burn "clean unvented" again, as the exact settings of the logs and burner are critical or they make some soot, etc.

If it were mine I'd open the damper a bit and make sure I have CO and smoke detectors nearby to check on it.

 

[newguy09]

So leave the damper say half open? Would that be sufficient if it happened to be vented or like you say vent free but no longer as clean burning as designed?

 

[webbie]

Ideally you can find a tag attached to it somewhere. If it were mine, I would fire it up without the logs on it with the damper fully opened and let it warm up for a long while. If the flame is mostly blue, that confirms it's probably a unvented or a "reduced venting" log.

Another hint is to look closer at the pilot as Daksy mentioned. Unvented use an ODS tube. Look here:
https://www.hearth.com/econtent/index.php/articles/how_gas_works

about 1/2 way down the page for how an ODS works. If your pilot looks like that, it's probably unvented. This means a nice blue pilot flame and that tube....

IF you determine it to be unvented, chances are that just opening the damper a small amount would vent the small amount of products of combustion. You can test this somewhat buy holding a match or lighter near the top front of the fireplace (lintel). If it gets sucked in, then you know the combustion products are headed in and up the flue. If it comes back toward the room, it means they are spilling out.

IMHO, unvented only work well when fairly new and in perfect condition. After years of use and wear, they can get screwed up.