Originally Posted By: dwickline This post was automatically imported from our archived forum.
I inspected an oil furnace and when looking at the duct I noticed that there was stuff that looked like creosote that had run down the sides of the duct. The top of the lower sections (male) were inserted into the bottom of the upper sections (female). At first I thought that they were installed backward but then thought that if they were installed the other way that there was a possibility of exhaust fumes escaping. Now I’m a little confused. Please help!
Originally Posted By: dedwards This post was automatically imported from our archived forum.
All of my publications, texts show the flue installed opposite of what you say you observed. The male sections should fit down into the next lower section on top of the female end of the flue, otherwise creosote and condensation moisture will do exactly what you saw. The liquids will form on the inside of the flue and when it comes to the joint it will run out and down the outside wall of the flue. Interestly enough I was just reading up on this last evening in HVAC textbook…I need to get a life…