What are the safety/legal considerations for safely re-routing gas combustion ducts?
I have a two-story house with two gas combustion air ducts. The
left duct serves a fireplace that is not in use and will be removed. The
right duct serves both the water heater and furnace. I would like to remove the highlighted yellow sections and re-route the water heater + furnace exhaust duct to the
left duct, and cap/kill the fireplace. The
right duct is in the middle of a room on the second floor; the main intent is to remove the
right duct that was in a removed wall to be completely removed. There is currently 24" between the 6" round ducts.
Section 304.11 of the 2015 Washington State Fuel Gas Code doesn't specify the required slope for horizontal runs, only:
- Horizontal upper combustion air ducts shall not slope downward toward the source of combustion air.