On Monday, February 16, 2015 at 11:44:06 PM UTC-5, HVAC Man wrote:
replying to intersoft4you, HVAC Man wrote:
intersoft4you wrote:

Hi everybody,
I have just installed new High Efficiency furnace (Keeprite). In the
manual 2 pipes are depicted (Exhaust and intake) running outside of the
house. However, the installer has left the intake pipe inside of the
basement (the pipe is about 20 inches long above the furnace). He says
it's OK to have an intake pipe to suck the air from within the
basement. Is it?
Thanks a lot!
Viktor



A high efficiency furnace should draw air from the same pressure zone !
Meaning the inlet air pipe and the exhaust air pipe should be in close
proximity to one another allowing equal pressure changes. Both pipes
should always be installed on the same side of the house as well. Whomever
said you are allowed to to draw intake air from the basement is just
looking to make some easy money on nuisance pressure sensor trips....


Nonsense. Many furnaces can be installed using either outside
combustion air or inside. It's permitted per the manufacturer's
installation instructions. In most cases it makes more sense to
use outside air, especially if the furnace is located in a heated
space, because if inside air is used, the makeup cold air will be
drawn in to the structure from outside through leakage.