I just installed a new PSG caddy Furnace in my upstate NY home. it was working well. For safety reasons, I hired a chimney sweep to inspect a few concerns I had regarding the chimney as well as WC pressure. This is our first experience delving into wood burning other than using our fireplace occasionally. The professional said the chimney was looking great, but we had -.01 for wc. The Caddyy calls for -.02 to -.06. We were way to far from our chimney, 17 horizontal feet, which is what it had been prior for our oil furnance. No where in the manual or elsewhere had I read any info on the maximum horizontal length, otherwise I would have not proceeded with plans. After a call to PSG, the tech said it cannot exceed 7 feet. After taking time to dig out 432 cubit ft of dirt, stone & bedrock from a crawl space in my 1811 home, I determined it was better for plan B. We could not get any closer to our existing furnance. So I decided to move it closer to an outside wall an build a chimney. Through various sources, I hear controversial thoughts about whether to use insulated double wall pipe or more expensive triple wall pipe. The horizontal run will be about 5 feet and vertical height will be about 17 ft. The chimney will be outside of a wall and gabled roof. Because I am concerned about safety issues and chimney fires, I wanted t make sure I do the right thing and all this stuff is outside my expertise. It seems like its already been a long winter, lol. Which do I use, triple or double? And... will he insurance companies look for something specific? Thanks for your help and generosity.