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Sun Jul 26, 2020 3:12 pm

Glad someone brought this thread back! So my dual system has been working great for a couple of years now. Here's how I did the controls:

Front and rear are separate, the only slight bummer is that it's a long reach to the rear knobs. Better like your passenger 8) . On a hot day, I'll start out with both front and rear running to cool the van off quickly, then cut down to front only if it's just me driving, or leave the rear on low if the kids are in the back seat. Have had no issues with the rear icing up.

Notes from the install:

Running low on time and energy, and wanting to finish the project up before a trip I also ended up having Stephan's (SAH) make the hoses and charge the system up for me. They did a fantastic job, and used R134a rather than Redtek, which I'm actually very pleased with as well. Now it will be an easy matter if it ever needs to get leak checked/topped up while on the road (most shops will only work on R134a).

I ended up going with this compressor, which is supposed to be larger capacity than the stock 1.8T compressor:

http://store.sanden.com/index.php/4805.html

Went with the new condenser from Gowesty, as well as new drier in the stock location. I also pulled the "diffuser" thingy out from the stock rear A/C and made a little grille panel to clean it up:

And fabbed up this nifty new air dam, getting ready to try it out with some big highway miles to NV/ID/WY/MT next week:

Sat Aug 07, 2021 8:32 pm

I’m back at it again,

So I installed just the front last year but alas it isn’t really enough to get the van cooled down on really hot days .

My plan with the rear is to have it come on the same as the front no separate zones. I would run both systems of the same (one) fan switch. I.e front on speed one rear on speed one and so on. My main questions are on the wiring side. And I’m not quite sure how to wire it all up.

- will I need to wire in the rear thermostat (probe in the evap) for the rear or would the front one on the I dash system suffice? How does this prob/thermosts work?

- do I need the ambient temp sensor in the system?

Sun Aug 08, 2021 5:03 am

Just my opinion here.

It should be mentioned that I did not install my planned second zone, that Van is gone and my Tintop I now have has the ducts to the front effectively cooling the cab area.

Anyway.......

Ambient sensor is simply a safety device protecting your system from running and possibly getting damaged in cold weather.

I would NOT have both fans on the same switch, you will have different cooling needs depending upon many factors. Sun, engine radiant heat, number of passengers, etc,

The thermostat probe does control temperature by cycling the clutch as needed but it also prevents coil freeze up.
Ice can build up on the fins and block air flow. When that happens the refrigerant cannot dump its heat load and things grind to a halt.

The Vanagon rear system uses an electronic probe. Many system use a gas filled probe into the temperature switch.

How you will wire in freeze up protection on the thermostat not controlling the clutch cycling?
I don't know.
Maybe a relay that the electric probe activates which shuts down the clutch?

Dave

Sun Aug 08, 2021 10:24 pm

Hi Dave,

The ambient sensor I will leave out.
I should also mention that my Westy was a non ac van so there is no existing wiring present which is the main reason do for tryin to simplify.

You are correct my front (vintage air super gen 2) ac setup is gas capillary prob and the rear westfalia ac set up is an electronic prob…

I am now in agreement on having the rear blower on a separate switch.

My Issue is I would like to simplify the system and run it more as one system instead of two systems.

I am wondering would wiring the rear thermostat somewhere between the front ac thermostat wire that runs to the trinary switch work? My thinking is the rear thermostat would protect against icing up, the front would take care of the rest.

Have the rear blower/fans on their own variable speed switch .

Mon Aug 09, 2021 11:15 am

I'm sorry but I am basically electrically challenged.

The electronic probe will need some sort of a unit to interpret data the probe sends as it is freezing cold ..... ice up danger! turn off compressor!

But I don't know what that magic box is.

They exist, VW's thermostat box is readily available but it is close to $200.

Dave

Mon Aug 30, 2021 12:15 am

Roughly how many oz’s of r134a is needed for a dual ac setup?
oe setup in the rear and Vintage air super gen 2 up front?

System will be completely empty.

Mon Aug 30, 2021 7:42 am

djsixbillion wrote: Glad someone brought this thread back! So my dual system has been working great for a couple of years now. Here's how I did the controls:

=D> Beautiful Syncro and a 1.8t to boot! #daydreams #oneday