I have an air conditioning unit in my attic. Only in the winter do the vents leak water down the ceiling. The 6" duct is r6, and I wrapped the ducts with insulation. The house is truss roof construction, and the ductwork and vents I have the most problems with are an all downward chase to the vent. I have tried everything. Please help.
Thomas, Ravenna, OH
A lot depends on how much water you are seeing. When you have a cold attic and a warm house, the air from the home may be entering the ducts in the cold attic, and this may be causing condensation. You said that you wrapped the ducts with insulation. Make sure the insulation is adequate so that moisture does not form inside the pipe.The chase to which you are referring may be an air chase or it could be a chase that needs a fired stop valve to block any attic air from entering the chase. If the ducts in the attic are used for cooling but not heating, I would shut off the vents in cooler weather. I suggest you contact a professional HVAC contractor to inspect your air conditioning system.
Condensation is the most likely culprit if the dripping sound is definitely tied to when the heat is running. If the vent pipe is not properly insulated, moisture could be forming on the inside of the pipe, especially if a gas water heater vent system is connected to the vent system for the furnace. If enough condensate forms, it will drip down and hit the section of vent pipe below it. If the vent pipe is extending through the attic, and it is not a double-wall pipe, and/or not sufficiently insulated, it is more likely that condensation is occurring.