Tim,
I just recently had a new 90+ high efficiency gas furnace (Frigidaire FG6RC) installed and the contractor installed the exhaust vent but did not install the piping for the combustion air vent and I was wondering if this was normal or if it should have been installed? The furnace is located in the basement so I am assuming that currently the combustion air is being pulled from the basement and not outside but I am not certain how everything functions and whether or not this configuration could cause problems.
Thanks,
Tom
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Tom,
Believe it or not some new furnaces can be installed in this manner. The first thing you need to do is look through the written installation instructions and see if this model can be installed without a direct combustion air inlet. The second issue is whether your local code authorities permit this type of installation. Not all do.
I can tell you that I would absolutely install a make-up air inlet at the very least. This inlet should be located as close as possible to the furnace. If the furnace is not near an exterior wall, then I would pipe the make-up air to the furnace. Read my past column about make-up air. Every home with fuel-burning appliances, exhaust fans, central vacuums, etc. should have make-up air.
Tim Carter
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