Proudly American
Read the drawing from each end
Start at the roof end of the drawing. The chimney carries exhaust from the firebox. Now look for a separate connection running toward an exterior inlet. In the Heatilator ICON example, the instructions illustrate the inlet hood and its duct independently of the chimney. Another fireplace may use different hardware or have no such control. Use the example to distinguish functions, then find the instructions that match the nameplate on yours.
When wall work changes the picture
Imagine the controls in the room still move, but a siding project has covered an opening previously visible outside. Movement at the handle would tell you very little about the far end of that route. If an old photo of the wall already exists, keep it with the project description. Do not remove siding, cap a mystery inlet against drafts or force a stiff control to establish which duct it serves.
Leave the next owner a usable key
Once the model and installed controls are identified, note the manual page, identify each control in plain language and retain the manufacturer’s operating sequence. An inherited sticker that says simply “open” can cause exactly the same confusion next season. If the version in the room has a different layout from the drawing, have the discrepancy inspected before any use.