To install a Marco fireplace, first select a location for the unit that has a non-combustible floor and is not near air conditioning vents, pipes or electrical wiring. After framing the location, slide the fireplace into position, and assemble the outside air kit. When the duct assembly is complete, put the double-wall chimney system in place. Begin this process by fitting the first inner pipe into the starting collar on the top of the fireplace.
Fit the outer section of the pipe over the inner section, securing it to the outer starting collar and aligning it to the wire spacer locks. Repeat these steps for each section of the chimney until you reach the ceiling. Cover the end of the pipe and cut out the hole for the chimney directly above it. Install fireplace spacers at the points where the chimney passes through floors and joists. Locate and cut a hole for the chimney to exit the roof, then continue to extend the chimney until it passes through the roof opening.
Remove the roof shingles before installing the flashing. Waterproof the top of the chimney by applying caulking and a storm collar. Caulk any seams that could cause leaks, and paint the outdoor portions of the chimney to protect them from rust. At a minimum, chimney height should be 15 feet; higher chimneys may need pipe support installation to keep them secure.
Install the gas line to the fireplace, and test it for leaks. Shut off the gas, and open the fireplace damper before installing the gas log lighter. After the gas log is in place, turn the gas back on, and light the log with a match. Turn the gas off after the log begins to burn. Finish the project by installing the fireplace facing and hearth detailing.