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Condensor question

Turbofiat on Wed July 13, 2011 8:34 AM User is offline

I may have made a design flaw to my custom A/C system. Something I didn't realize until now.

I have the inlet (from compressor) going in the bottom of the condensor and the outlet going to the dryer coming off the top.

Shouldn't it be the other way around? Or does it even matter? Gas should be condensing in the top of the condensor then liquid should be at the bottom.

Unless there is enough pressure being produced by the compressor to force the liquid out the top of the condensor.

For whatever reason the system seems to work OK and the temperatures coming out of the vents are close to what my '03 Subaru produces in recirc mode anyway.

I won't make this mistake when I A/C my Yugo this winter.

I had very little space to work with and routing the hoses was the biggest challange:

Click here for photos of my system

Edited: Wed July 13, 2011 at 8:35 AM by Turbofiat

mk378 on Wed July 13, 2011 9:04 AM User is offline

It's more work for the compressor to keep pushing the liquid up and out, so yes it would work better flowing from top to bottom. How much better would be hard to guess.

Turbofiat on Wed July 13, 2011 10:30 AM User is offline

Initially the pressures were 180# on the high side and 40# on the low side.

I just checked the low side the other day and it was upto 45#. But it was 10 to 15 degrees hotter that day when I checked it.

Turbofiat on Wed July 13, 2011 5:02 PM User is offline

I found some diagrams off the internet. These diagrams may or may not mean anything as far as the direction is concerned.

I beleive I have a paralle flow model.

Here is the way my system is routed:

Shows this opposite direction:

Edited: Wed July 13, 2011 at 5:04 PM by Turbofiat

jga2z on Wed July 13, 2011 8:28 PM User is offline

Thanks for the nice collection of diagrams.
You didn't say if your system is r 12 or r134a or ? With a parallel flow condenser I don't think it would make too much difference. With a serpentine loop condenser I don't think it would work as efficiently.
You might possibly still need a bit more refrigerant.

Turbofiat on Thu July 14, 2011 9:38 AM User is offline

It's a 134a system.

mk378 on Thu July 14, 2011 9:48 AM User is offline

Notice also that receiver-driers are sensitive to gravity and flow direction. They are designed to let the mostly liquid output of the condenser enter at the top. The liquid drops to the bottom and then feeds to the TXV through a bottom outlet, or more usually, an internal dip tube. Connected backwards, the entire unit would need to fill up with liquid before any reaches the TXV, which negates it's purpose as a buffer tank to keep the condenser clear of liquid.

So when building a custom system it's essential to mount the receiver vertically and plumb it so the designated "out" goes to the TXV.

The first diagram has some other stuff wrong but it is a good depiction of what happens inside the receiver-drier of a TXV system. The second one shows a dip tube setup.

Edited: Thu July 14, 2011 at 9:54 AM by mk378

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