Moist hot air seeping out of vent

Old 09-20-17, 12:07 AM
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Moist hot air seeping out of vent


There re seems to be warm, moist air flowing out of the air vent in our bathrooms, but the central air system is off. Setting is actually set to off, not heat or cool, and the fan is also off. None of that matters. The air keeps pouring in.

The air air pressure isn't great. So it's not blowing all hat hard. Yet it is unmistakably flowing out.

Does this sound familiar to any of you? Do you know what might be happening? Thank you so much in advance for your help.

Old 09-20-17, 03:13 AM
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Is the furnace in the attic ?
Old 09-20-17, 05:20 AM
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I would inspect the ducts. Maybe there is a hole or a line has disconnected.

Are your ducts insulated?
Old 09-20-17, 05:49 AM
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In the summer the cooler air inside a house leaks out of the lower levels and allows warmer air to flow in from the upper areas, called reverse stack effect. Check all ducts as suggested and inspect the backflow damper, one may be inside the fan and the other at the outlet. The usually don't close 100%. There are other designs that can provide full closure for backdrafting.


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