Originally Posted By: cmccann This post was automatically imported from our archived forum.
During an inspection today I saw for the first time a 90% forced air furnace using one pipe for both exhaust and induced air. Looked through code check briefly, but couldn’t find the proper reference. The unit was installed 2003 with city inspectors final sticker, is this correct? If so how can this be possible?
Originally Posted By: Lee Hammerstein This post was automatically imported from our archived forum.
Technically it is not one pipe for exhaust vent and intake. There are two pipes at the “Y” fitting. The outer is the intake and the inner is the exhaust vent. It continues to the termination as a two pipe system. It requires a special fitting and a special termination. It also can be used horizontally to vent through a side wall.
Originally Posted By: rcloyd This post was automatically imported from our archived forum.
Chuck,
It is called a concentric pipe system. As mentioned in earlier posts, at the Y it splits into two pipes (on the interior) this allows for only one penetration through the roof or wall. Less holes in the building envelope is a good thing. these systems should be installed in accordance with local codes and the manufacturer's instructions.
