The framing should have waited until you selected the unit.

Although these units have very few moving parts, they do need periodic preventive maintenance, probably best done by a professional. Ours, a different brand, is still too new to need any maintenance -- preventive or otherwise. How often you do it depends in part on how much you use it, assuming that certain components get dirty and need cleaning out. I think once a year is probably too often unless you use it as a main source of heat. But I haven't anwered your question. I think it needs diagnosis by a professional who knows exactly what to do to troubleshoot. Here's my speculation: If the thing sometimes stops firing spontaneously, and then goes back on spontaneously, that suggests that the vent that provides oxygen to feed the combustion may be partly clogged. That should not happen if the right kind of cap was installed on the chimney, but it's still possible after a period of time. If you can easily get to the chimney top without risking life and limb, go up there and see if anything obvious is clogging it.

Hi there. Did you end up choosing one of these fireplaces? It seems I have been looking at all of the models you mentioned, and our fireplace width will be 6'10" wide, so we are in a similar situation. Let me know how it worked out for you, Thank you.

Maybe try the home decorating forum.