B Vent fireplace help please.

[Firm Foundation]

This double sided B vent gas fireplace is burning a low blue flame, but when the glass front is opened the flame rises to a nice high orange flame, so I believe it's getting poor ventilation. The client has had the dealer out and they are saying that's the way it's supposed to burn (low blue), and the builder is at a loss as to how to improve so he added the larger vent pictured below in the attic.

1. Does this vent in the attic appear to be against fire code?

2. What would you recommend as to how to fix the fireplace?

All opinions welcome, and thanks!

[AHI in AR]

All the gas double sided fireplaces I am familiar with are designed for sealed use only. In other words, you can't remove one side of the glass front during use; they are fixed in place except when removed for cleaning. (Admittedly, I haven't seen all brands.) Clearly, the glass panel on the front side in the photo is a fixed panel since it's one piece.

There is a built in air inlet. Unless that was not installed, you should have no problems getting air and using it as intended with both glass panels installed. As you stated, the unit works fine until a side is opened. There's no need to modify the manufacturer's system, and to do so would not be a good idea. I'd return the system to the configuration the mfr. requires.

I can't tell what the attic shot reveals. That looks more like an insulation shield than a vent modification.

More info would help.

[Nolan Kienitz]

Kevin made referance to this: Where is the "make-up" or "supply air" vent.

When you open the doors and the flame grows up it is taking that air to burn the flame from your living space.

Should be a make-up air vent from the firebox to the home's exterior (NOT attic).

Not sure what the deal is with the image in the attic around the B-Vent.

[Firm Foundation]

Kevin made referance to this: Where is the "make-up" or "supply air" vent.

When you open the doors and the flame grows up it is taking that air to burn the flame from your living space.

Should be a make-up air vent from the firebox to the home's exterior (NOT attic).

Not sure what the deal is with the image in the attic around the B-Vent.

Maybe I miscommuicated. This is an enclosed system. When both sides of the glass are shut, the flame is very low and blue, and does not extend up above the logs....however when I opened the glass, the flame rose to what I would call a normal height and turned orange. Is this due to poor air intake? What would you recommend to the homeowner? Their builder says it's working correctly and told them they could install an exterior air vent but they he was not paying for it.

[AHI in AR]

If the flame is blue with the glass doors in place as designed, it is getting the correct amount of oxygen. Blue indicates clean combustion. If you want a larger flame, most units have a control valve underneath the bottom of the firebox that adjusts the amount of gas fed to the flames. Turn that up if you want a larger flame. My experience with this type of unit is that they generally don't produce really large flames no matter what. They're not designed to do that.

[Scottpat]

As others have said this is how that unit is suppose to work, it sounds like an unvented log unit might have been used. If they want a higher flame yellow (not as efficient) they need a vented log system.

In the photo of the vent pipe in the attic: If that is not a metal spacer keeping the insulation from around the flue pipe, then the insulation needs to be moved away from it so you have a 1" clearance or more around it.

Did you by chance get the brand and model number of the log set?

[Firm Foundation]

thanks everyone.