Direct Vent Gas Fireplace Smell

Old 04-06-14, 07:33 PM
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Direct Vent Gas Fireplace Smell

Hello, I recently purchased a home with a direct vent gas fireplace. It is a Monessen, model BDV500NV. I previously had somewhat limited knowledge of gas fireplaces or fireplaces in general, but have started to read a lot online due to the strange smell that I am noticing with the fireplace lit. (short description)

(longer, more detailed description) When first using the fireplace I noticed a smell. I didn't know how normal it was but also thought when I first run my furnace in the fall it smells a bit too. According to the previous owner, they seldom used the fireplace, possibly only once or twice, so I thought it may be more of a "first time started in a while" type smell. I do not believe they are the original owners of the fireplace, so I don't know how much it was used prior to them. When my smoke detectors went off that caused me concern and I turned it off, opened windows, etc.

My main question is what could be causing the smell and potential smoke (that isn't visible). I don't believe it to be carbon monoxide since the CO detector doesn't go off, only the smoke detector. I have also reviewed the installation/operating manual for this model and only find that during the FIRST use of the fireplace, it should be used for about 10 hours to burn off smells that are due to the manufacturing process.

Other things I noticed are that it doesn't appear to be set up the same as noted in the manual or similar to other vented gas fireplaces I have seen online. The vent out the side of the house does not appear to have two chambers (one for air intake, one for exhaust), rather it has one main chamber, assuming for exhaust (?). At the bottom of the firebox/where the gas burner/logs are, there appear to be 3-4 holes potentially for letting air in for combustion, and there are also rectangular holes in the top part of the firebox/combustion area that seem to have some type of filter/foam installed. While these do not appear in the manual, it does not appear to be a random modification, the fireplace looks to be manufactured with those holes in place.

I do have a service call in to a technician, but if anyone has any advice or suggestions for me that are quick/simple fixes, I may be able to cancel the service call, etc.

Thank you!
Old 04-06-14, 08:20 PM
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Welcome to the forums.

I was looking thru the manual and I didn't find them referencing single wall flue pipe. That looks like it should strictly be a concentric flue system installed there.

If that was set up as single flue it could conceivably be drawing the exhaust gas right back thru the fresh air intake. I would think that would create a fireplace that would be running extremely hot.

My recommendation is allow the technician to check it out. That's not an area where you want any kind of problem. Please stop back and tells us what his determination is.

Monessen Manuals FBDV REV 2014.pdf
Old 05-01-14, 04:49 PM
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Smoke detectors - Very sensitive smoke detectors and especially ionizing smoke detectors are known to false alarm with open flames. A photocell type smoke detector or a heat detector (if permitted) might not false alarm. I have a hard wired photocell system and it has never false alarmed. Does the alarm sound if it is in the kitchen and the stove is on without anything being cooked?

The fire place you have seems to be arraigned to send most of the heat up the chimney, It is mostly for show if I understand it correctly.

You might post pictures of what is concerning you. I cannot tell if you set up is meant to vent into the room to provide heat, or if the logs are just for show with the heat going up the chimney.

Natural gas produces about a gallon of water for every 100000 BTU consumed. That water is in the air in the room. You can sense the high humidity. For me it is not a smell but I can sense it with my nose when I first encounter it, but after a minute I cannot sense it anymore. If that makes sense to you. You might check the humidity with and without the flame on.

If you have gas logs try operating the unit without them. There are claims that if they get dirty the dirt will burn.

You might consider paying a local pro to look the set up over. Find people that sell vent free fireplaces and heaters. They may have suggestions as to what can replace your set up.

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