Expert: James Ball - 1/11/2009

Question
A few weeks ago I noticed exhaust from my oil-fired forced air heating system getting into my bathroom. The heating unit and pipe are located in the crawl space beneath the bathroom and living room. The oil co said the smoke pipe was rotted going into the chimney base. I had that replaced and metal taped at all joints. This did not solve the problem. I called a CSIA chimney sweep. They inspected and found cracked clay pipe in my old chimney. $1300 and a new stainless steel liner later, I'm still having the problem. It seemed to stop right after the installation (for a few days) but now is back. The tech told me if odors come back to shorten the length of smoke pipe. It is 12 feet and the chimney is 20 feet high. Does this sound accurate to you? I'm wondering if everything is sealed, how can the fumes be getting out?

Answer
Hello Kristy, I am not sure what is going on with your set up, but yes the furnace smoke pipe could be shorter (moved closer to the short chimney) but why is the exhaust getting in the bath room?  is there a window in the crawl space? If so open it. Is there a bathroom exhaust fan if so tape it closed and see if either of those make a difference. then a wind deflection cap (wind down drafts)
Air in a chimney is going to do one of three things just sit there (no moment up or down) down draft from Wind pushing it or Negative pressure (hot air in the house or mechanical Exhaust fans Bathroom/Kitchen, close dryer, even the furnace (might be cracked)) in the house pulling it down
keep me posted
James