Here’s a tip for all the installers out there and new techs. On a new install read your installation manual get to know your equipment. This new system is 8 months old installed by another company. Furnace was tripping out on high limit. First thing I checked for was restrictions.....nothing. Then I thought blower motor to low of a speed raised the speed still tripping. Then I thought bad limit....nothing. The home owner had brought me all the paperwork that the installers had left. I sat back and read the install manual. What I had found was the flue was undersized by to many fittings. The flue was 15 feet long each 2in long radius elbow was meant for 6 feet and each long radius 45 was meant for 4 feet. This system had 3 long radius elbows and 2 long radius 45s. So adding that up we have fittings set for up to 26 feet for 2in pipe. I reduced the fittings down and went from a 390 degree temp down to 127. The furnace door was partially on because I was releasing all the excess heat to let it run overnight until morning so I can fix the flue. I reduced the amount of fittings down to 14.5 feet of pipe. So I’ll say again read the install manual they will save you a call back and when you do installs leave the book behind for the next service guy. He or she could use it.

Posted by Deleted (487a8b92) at 2021-05-13 02:41:12 UTC