A/C dripping from condensation?

[GregWeld]

Originally Posted by rkleypas

Greg,

What did they do to remedy the problem? I didn't get around to my proposed repair today and may want to hold off on my "engineering" until I find out how they fixed the problem. Thanks

I wish I knew - because I could share with you, but I have no clue what they did.

[KUL FIR CHICK N]

Originally Posted by dhutton

I sent the engineering manager of VA a PM with a link to this thread over on the other forum. Let's see if he replies.

Don

Hi Guys,

Sorry for my delay in seeing this post. Don sent the PM to me over on PT.com and I didn't have it set to email me when I received a new PM, so I didn't see it until I went on there this morning. It's fixed now so I should be able to respond to PMs in a timely manner.

There are several different issues being discussed on this thread, so I'll work to address them all one at a time.

First, Bill’s issue, as I understand it, is excessive condensation dripping from the EXTERIOR surfaces of the case, duct hoses, and possibly the refrigerant hoses. If, in fact, the condensate is dripping from the exterior of the system, this is not a system-related or defective-system issue. I wouldn't say it's necessarily "normal" either. It's just physics, and it's correctable. If I were troubleshooting your car in person, I'd start by looking for body leakage. The sweating issue you describe is the result of a constant supply of humid, outside air entering the vehicle while you drive. If the cabin is well sealed, with no outside air leakage, the A/C system will quickly dehumidify the air within the cabin, lowering the dew point to a level where there will be little to no condensation observed. I took some quick measurements this morning on one of our test cars so that I could describe this in detail. The ambient temperature this morning in San Antonio was about 85 degrees, and the dew point outside was about 70 degrees. With a dew point of 70 degrees, any surface that has a temperature of less than 70 degrees has the potential to condense water from the air. The further away from 70 the surface is (to the cold side), the faster condensate will form on the surface, just like it does on a soda can, as was described earlier in the thread.

Now, if I step into my vehicle, which has been sitting for several hours with the doors open, the dew point and temperature inside the car will be similar to the outside conditions. I close the doors, start the engine, and run the A/C on full power with the windows up. The dew point inside the car will immediately start to drop, and within about five minutes, the dew point inside the car will be around 45-50 degrees. The temperature of the air exiting the vents will be in the neighborhood of 40 degrees, and the exterior surfaces of the case and ducts will be in the neighborhood of 45-50 degrees. In this case, I would not expect to see any condensate form on the case and duct surfaces, no matter how long I wait. If I open the windows, the dew point inside the car will immediately start to rise, and condensation will begin to form on the cold duct and case surfaces. The air leaving the A/C vents is 40 degrees and has a dew point of 35 degrees, but the constant supply of humid outside air is mixing with the conditioned cabin air, raising both the temperature and the humidity in the cabin.

The fix for Bill, 69hugger’s condensation problem is probably going to be sealing up the kick panel vents, door and window seals, any holes in the firewall, sealing the shifter boot, and even the trunk seals. If the trunk seals are leaking, the low pressure at the rear of the car will draw air out through the trunk, which will cause negative pressure in the cabin, and draw outside air in through every crack and crevice in the body. The aforementioned insulation of the ducts and case would help, but it is more of a Band-Aid, masking the root problem. One thing that MUST be insulated is the suction line inside the cabin. All exposed metal surfaces of the suction line should be wrapped with "press tape" as supplied with all of our kits. The suction line can often run at or below freezing, and exposed portions of it will sweat profusely.

Please feel free to PM me, and I’ll do my best to help you correct this issue.

Respectfully,

Ryan Zwicker
Director of Engineering
Vintage Air, Inc.

[GregWeld]

NEW cars never have these condensation issues... or dripping.

[kwhizz]

I would think that the dripping would come from the condensation of humid air (these cars aren't sealed as tight as new cars) on the flexible plastic A/C hoses that have the cold air blowing thru them......the water condenses on the hose and drips off at the lowest point of the hose as routed behind the Dash.........Just my $.02

Ken

[GrabberGT]

Originally Posted by kwhizz

I would think that the dripping would come from the condensation of humid air (these cars aren't sealed as tight as new cars) on the flexible plastic A/C hoses that have the cold air blowing thru them......the water condenses on the hose and drips off at the lowest point of the hose as routed behind the Dash.........Just my $.02

Ken

I just had my system charged for the first time ever and this was my experience as well. Getting a few drips from the vent tubes while cruising down the hwy. My wife was more alarmed than I was.