the furnace runs fine with intake only part way on intake of furnace. However it goes out when fully installed. The pipe seems to be clear of any blockages? Is pipe too small 2" PVC? Too long with too many elbows 2-3 elbows roughly 25' long. Or it OK to just run it pulling part air from basement (which I've done for years)? But recent inspections trying to sell my home the inspector questioned it??