I have and chimney that is brick outside and inside there is a Martin Model SCF36 Serial Number 857757 inserted. Currently the previous owner inserted vented propane gas logs. Can I change out to a Ventless Gas logs system using this same Firebox? This firebox also has a space below and a small blower in place. The blower is sitting on Concrete not fire bricks. It looks like the original owner never plan to use this as a wood burning fireplace. Any information would be greatly appreciate.