Local codes usually mean nothing with cat 4, high efficency furnaces. the manufacturer’s installation instructions rule (except where the local codes are stricter, which never happens).
i have gone up against Chicago building code inspectors, many times, and they are not aware of the new 90+ requirements (Gee, think CE should be required for local building code inspectors? ).
Remember, a 90+ furnace with no combustion air intake is only 80+. Allowed, but not now it was designed.
Make sure that the PVC vent pipes have screens. Many past clients are complaining about roasted birds, now that they are running the furnaces. :shock:
Call me (see below) if you need to.
Hope this helps;