I'm looking at the thin gage steel behind the logset. That would warp inside of 15 minutes with a wood fire.

The "firebrick" is just pressed material, not real firebrick.

No, do not burn wood in that "fireplace". Use the gas unit as an entertainment source, not a heat source. They were never meant to be real heating appliances.

And go to a reputable stove shop and get a wood burning insert that's licensed to be placed in your firebox.

Now hold on guys. Yes, caution is absolutely required here. However, I have a builder grade fireplace that looks very similar to the OP's unit. Mine is designed for either wood or gas. My unit has the same cheesy thin metal like stuff. If you look at the other pics on flicker, you will see that the unit has a full above roof chase and what appears to be a spark cap. I believe my unit has one of those huge 14" flues which is common for these units. This one doesn't seem to be that large, which makes me wonder if it is indeed a wood burner. The top of the front of the unit also has something that looks like sheet metal extending down into the firebox that is different from mine and that makes me think of gas.

Remember, these are open fireplaces and don't really generate dramatic heat. My cheesy back fake bricks never got damaged in any way. So, two points: the 'fireplace' may indeed be designed for wood and you will need to check further; AND you aren't going to heat much with this thing either.

The question is, Can I convert my gas fireplace to a wood burning..........

The OP states it's gas, not both. The vinyl sided chimney proves it to me. It's gas only in my opinion.

SC: Actually the op states that it is gas NOW. I have EXACTLY the same situation visually, with the exception of that shiny metal piece near the roof of the firebox. Actually, the gas line that goes to my fireplace was never hooked up. Many homes in our subdivision are built with either gas or wood like mine. They all have vinyl covered chases. Of course the flue is tripple wall and those chases give plenty of room to fit them in.

Most gas only units don't have flues that go above the roof top. The op's does and it appears to have a spark arrester as well.

Easy solution:

Find out what brand and model it is. Then ask the manufacturer.

Christopher,

Exactly.

From the original post:
"My fireplace is brand "Marco" Model#: 792779D and they are out of business :-( "

I googled around a little and someone said that Lennox bought out Marco. Perhaps that would help.

You can also go over to www.hearth.com and ask the real experts.

What you appear to have is a wood burning fireplace that has a added set of vented gas logs installed. The ring you see at the top of the fire box is your damper handle and will open and close smoke access to the flu. You can remove the logs back to the steel pipe coming into the firebox and reinstall a appropriate log starter kit with a new grate (18 or 21 inch) and you are back to factory. Always a good idea to have the chimney cleaned and inspected before use ( there may be a reason they put the log set in ). Good luck.

Also the model number you posted is the serial number.