Vent Free Gas Logs

[mdharris68]

Any thoughts on vent free gas logs? I have a customer with a unit and Model # is VF-CL24-MIL. Can't find any MFG name, or anything else. Wondering what makes them burn CO free? This one puts off 26 PPM after cleaning burner, checking pressure and the like. Any help would be appreciated.

[logdoc_rob]

The mfg should be on the same tag where you found the model number. The high CO could be from improper log placement. Does it have fiber or concrete logs? I have seen where ceramic logs have become contaminated by dust, pet hair or "stuff" falling from the damper and burning.

Make sure that there is no flame impengment by the logs. That will surely cause CO issues.

[mdharris68]

Does that mean I could remove the logs and expect a clean burn?

[hearthman]

No. They were designed to burn with the logs. Removing them could cause stray air currents to distort the flames making it worse.

FYI, the CO level will be a little elevated from all the dust you've stirred up.

If a rating plate does not have a manufacturer, it should not be considered "listed" and therefore, removed. Rating plates should clearly identify the mfr., model, serial number, listing agency such as UL, Warnock Hersey, OMNI, or ETL labs and the ANSI Standard, which, in the case with ventfree is Z21.11.2b. It must also state the btu/hr input rating, min/max inlet gas pressures, manifold gas pressure, and any restrictions such as not listed for use in bedrooms, bathrooms, or mobile homes.

hth

[mdharris68]

Does that mean I could remove the logs and expect a clean burn?

I guess I should have clarified my question. In the process of figuring out what may be wrong with this log set, I was wondering if removing the logs from the burners could result in a complete burn? But since it requires the logs to be in place for the sake of stray air currents, I will need to figure out exactly how the logs are supposed to be set. There are a lot more to these logs than meets the eye.

[SeattlePioneer]

<<I guess I should have clarified my question. In the process of figuring out what may be wrong with this log set, I was wondering if removing the logs from the burners could result in a complete burn? But since it requires the logs to be in place for the sake of stray air currents, I will need to figure out exactly how the logs are supposed to be set. There are a lot more to these logs than meets the eye.
>>



Yes there is.


I was called out by a lawyer to inspect an unvented fireplace in a new house. The new owner had gone to the hospital with CO poisoning after using the gas fireplace in her new home.


I found that the logs had been arranged in an intutive way by the builder who installed the fireplace. They looked like they were decently arranged, but they produced a fair amount of CO that way.


I reinstalled the logs according to the installation manual and the CO produced dropped to a negligible level. The instructions given by the manual were quite complicated and hard to follow. I must have spent 20-30 minutes studying the instructions before I was satisfied I had the logs installed properly.


Of course, it's not unusual for poorly placed logs in vented fireplaces to produce soot and carbon monoxide too --- but when that happens, the hazardous gasses usually just go up the vent.

That's the problem with unvented fireplaces in my view, the margin of safety is narrow. Everything has to be right or someone may wind up in the hospital. And it's quite common for things not to be all right.



Seattle Pioneer

[Grinder]

And remember - there is a reason ventless fireplaces are illegal in Wisconsin and Minnesota.

OH - nevermind.

[fireplaceguru]

The unit you mention is made by Hargrove I beleive, the first letters are the same as what they list ( VF-CL24 ). You said the unit was producing 26ppm CO, which would place it in the highest level allowable for the vent free standards, Eg. Ultimate CO2 12.2% divide by actual recorded CO2 x 26ppm CO = ___ppm AFCO, Maximum allowed 200ppm AFCO. I would consider that reading you took as high. Log placement is critical with most vent free units and with units coming out with embers now it is even more critical.