How to stop overhead duct from dripping water on the kitchen floor?

[kath]

• I closed the louvered vent below the heating /AC vent. A few days later it dripped more from the screws. Condensation had gathered over the closed louvers. No other vent drips. it happens only in early morning.

[udarrell]

If the temperature of any of the duct system or register gets below the dew point, moisture will condense on it & drip.

Perhaps, the cooler outdoor air drops the condenser & evaporator pressure/temps too low causing those areas of the system to drop below the dew point.

Maybe the indoor blower airflow CFM is too low...resulting in too low an evap heat load(?)

You could install a damper at the branch take-off to the kitchen duct run & close it; I'd address the other factors first....

Also, is cooking in the kitchen producing a rise in room humidity?

[kath]

Thanks - maybe there's an outside source of air going into duct? Dripping happens no where else in house, and there's no cooking in kitchen that early in am. It happens 7-8 am and then stops.

[catmanacman]

does your system come out of night set back at that time

[kath]

I just discovered that vent doesn't drip before I take shower on floor above; vent does drip onto floor after shower. Groan.