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Here' one for the brain trust:

A 44,000 btu furnace with a draft inducing blower (right flue)

A 88,000 btu furnace with a draft inducing blower (center flue)

And a 75,000 btu gas water heater - gravity (left flue)

ALL share this flue. It seems to me that it should have stepped up another size after the third flue joined in. Undersized? Any thought?

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And, all three units are crammed into a 6 x 9 unvented room in the finished basement ... hmm....

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You know that with my second grade math skills I can't do the math for you but the flue must equal the largest connector plus 50% of all others. Get out a pencil.



Do you mean that the cross sectional area of the main flue must equal the area of the largest flue plus 50% of the combined areas of the remaining flues? Where does this rule come from?


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