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Why is my AC box condensing and dripping?

Yes they use an expansion valve... Flow all the time is normal, It regulates/restricts flow to reduce evaporator pressure/temperature... To much flow would raise the pressure & therefore the temperature....

He shows a picture of the condensate drain & states that it is working...
With the drain working and the system blowing very cold air and making the HVAC plenum icy cold, it sounds like the expansion valve has failed and its freezing up the evap core. I've seen them turn into blocks of ice because the valve failed, no regulating and it just freezes right up. Just hope he can get it "fixed" correctly.
 
Or you evacuate the system dry and recharge with the Measured/weighed amount of refrigerant that the a/c manufacturers recommend. This info is on the sticker in your engine compartment as well as your Factory Service Manual.

Not for a 134 conversion it isn't.
 
With the drain working and the system blowing very cold air and making the HVAC plenum icy cold, it sounds like the expansion valve has failed and its freezing up the evap core. I've seen them turn into blocks of ice because the valve failed, no regulating and it just freezes right up. Just hope he can get it "fixed" correctly.

Interesting. I thought this was addressed as not an issue early in the thread.
 
Interesting. I thought this was addressed as not an issue early in the thread.
Yup, just going off what I've seen and learned. The valve regulates the amount of freon flow to the evap core to keep it from freezing up, if it fails you can get full flow at all times and it can freeze the core up like one of those old time ice box's. The valve has a diaphragm and a tube that is placed in the air flow post evap core. As the air temp changes inside the tube it actuates the valve to increase or decrease the freon flow to keep it at the optimal temp without freezing up the core. I turned wrench's for a few years professionally but I still hate A/C work they are sooo finicky. I would look at all the other issues that have been raised first, because if it turns out the valve is the problem you will have to open the system up to replace it. Hope this helps.
 
Yes they use an expansion valve... Flow all the time is normal, It regulates/restricts flow to reduce evaporator pressure/temperature... To much flow would raise the pressure & therefore the temperature....

He shows a picture of the condensate drain & states that it is working...

The origional Mopar A/C systems using the V2 compressor running Freon 12 refrigerant, used a cross connected thermostatic expansion valve on the inlet to the evaporator to conttol the volume and pressure and temperature delivered to the evaporator. The x-over connection allows for a more accurate refrigerant delivery to prevent icing (too much refrigerant) or starving (not enough refrigerant) of the evaporator. In addition, the compressor had a Evaporator Pressure Regulator (EPR) in the suction inlet of the compressor. It's purpose is to maintain evaporator outlet pressure at ~ 35/37 PSI, to prevent evaporator icing. At the 35/37 psi set point, the saturated (super heated) gas temperature of the refrigerant, the evaporator is running at ~ 34° F. Any colder, the possibility of the accumulated condensate on the air side of the evaporator may occur, especially at low blower speeds and high humidity conditions. This was Chrysler's attempt to provide a first class system under all operating conditions. When retrofitting the system to use R-134A or R-1334YF, this component must be removed, as those refrigerants operate at different pressures and temperatures. Judt my opinion of course.
BOB RENTON
 
Looks like an expansion valve is fairly cheap ,as is a thermostat replacement for the EPR.

I'll try purging some 134, and if that doesn't help, I guess I'll replace both valves.

SUCKS, cause it's blowing GREAT.
 
Looks like an expansion valve is fairly cheap ,as is a thermostat replacement for the EPR.

I'll try purging some 134, and if that doesn't help, I guess I'll replace both valves.

SUCKS, cause it's blowing GREAT.
If you are converting to R134A from R12, to need to REMOVE the EPR VALVE from the compressor inlet. The TXV located on the liquid line at the evaporator inket, must be compatible with the R134A refrigerant as it has different specific heat characteristics and different evaporator operating pressures. If the system has been open, you should EVACUATE the system to remove the air, as it is a NON-CONDENSABLE, and will impede refrigerant performance.
BOB RENTON
 
It was "professionally" converted prior to my ownership.

Of course what that means to you and I may not be the same as what it meant to the PO or the person that did the work.

I did find one O ring that was not the green 134 compliant type.
 
It was "professionally" converted prior to my ownership.

Of course what that means to you and I may not be the same as what it meant to the PO or the person that did the work.

I did find one O ring that was not the green 134 compliant type.
I understand.....most "professional" HVAC people assume that the owner of the vehicle knows ZERO about how the system works....therefore are short on explanations. Just remember one important aspect: the A/C system does not make cold.....it removes heat....... (fourth law of thermodynamics)......
BOB RENTON
 
Looks like an expansion valve is fairly cheap ,as is a thermostat replacement for the EPR.

I'll try purging some 134, and if that doesn't help, I guess I'll replace both valves.

SUCKS, cause it's blowing GREAT.
Down load a presure temp chart for 134 and it will aid you diagnosing your charge. Make sure the TXVs bulb is tight against the line and that there 8s no corrosion between it and the line.
I still think your coil temp is below the saturation temp which is causing the box to condensate and if its doing it, you may want to look under your dash and see if your ductwork is as well especially if its been replaced with the newer style. The older stuff was thicker and seemed to have better insulating characteristics.
 
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I had access to one of those charts.

The low side never got anywhere close to 50. 25-30 maybe.
The high side was almost 200.

...but was blowing 45 degrees.

IIRC the temp that day was 95-ish.

Everything is OEM except the port adapters, what ever else was done during the conversion, and the dryer and relief and valve and o ring I just installed.
 
Drip tube from under dash is working (see pic in OP).

I even fled off some of the gasket between the two box halves when I was fixing the bent gasket.

The gasket where the tube exits blocks about 3/8" of the passage and tends to hold water in that side of the box.
 
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