Mike in Arkansas· Registered
Discussion Starter · #1 ·
A 100 year old house with updated HVAC currently but replacing with high efficiency zoned equipment. I have the upstairs done and am working on the downstairs now. Equipment will be installed in the basement. Its a 2 stage induced draft 50,000 BTU 80 plus non condensing furnace with an 18 SEER 2 ton AC. Optionally I may use a 90+ condensing furnace. Presently, the old induced draft heating unit (155,000 BTU) vents into an old 8 inch cement flue original to the house that runs from the basement to roof. Existing natural draft water heater also vents to this flue. The bottom of the flue is sealed. Is it safe to vent the new equipment into this flue? It is sound all the way to the roof so leaks should not be a problem. I suppose if I opt for the 90+ condensing unit it would no be acceptable because of the condensation but what about the non condensing unit?