Question: I am installing a pellet stove to replace my wood burner.My masonry chimney is in perfect condition .Do I have to decrease the size of venting to 4 ? Would it be practical to install a 4 regular stove pipe as a liner or does it have to be a stainless steel liner ? Thank you. Answer: You do need to line it for proper operation. Stainless would be the best, but if you don't mind replacing the pipe every 2-5 years (expected life inside your chimney), than you could get by with the regular stovepipe. Perhaps galvanized stovepipe would last longer than black pipe.