[header] How to install a chimney liner [title] Inspect the chimney. [step] Use a light source on a string (or an inspection camera if you have one) to look for bends, or restrictions that could interfere with pulling the liner through. [title] Determine the correct diameter of the liner. 
[step] If for a wood stove/insert, consult the owners manual for proper sizing. For an open fireplace, look for a chart or calculator online.