85 Weekender AC overhaul

[Abscate]

[AZ Landshaper]

ambient temp was 98 degrees.
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85 Weekender w/ EJ22
Previously
64, 71, 72, 73, 76, 81, 84, 85 & 87 Campmobiles and Westfalias
and a 67 bug.

[Farf]

How much refrigerant did you put in? What did you use for supplemental cooling of the condenser? Does your R/D have a sight glass on it?

[AZ Landshaper]

I used about three cans of red tek refrigerant.

My fan was running, did I still need the box fan? Theres one over site if so.

Gonna look at the site glass. There's def one there.
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85 Weekender w/ EJ22
Previously
64, 71, 72, 73, 76, 81, 84, 85 & 87 Campmobiles and Westfalias
and a 67 bug.

[Farf]

200 psig @ 98F without a box fan is seems low. I'd try adding a bit more refrigerant along with using a box fan or water (very fine) mist on the condenser, allow the condenser fan to suck the mist in, don't spray it directly on the condenser. Take a look at your sight glass, ideally you want a solid liquid going into your TXV. At the ambient temp you are working with and using a blended refrigerant you will see bubbles, they should collapse by the time they hit the TXV. The bubbles should not be excessive. Be slow and careful. Watch your pressures.

[MarkWard]

What are the pressures at 2500 rpm?

[Abscate]

Try taking it for a spin to see if the delta goes up with the car moving. At 98F, condesor will need flow
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[AZ Landshaper]

1500 rpm

900 RPM

2500 RPM

2500 RPM after 3 mins

Site glass looks cloudy and quite difficult to see.


As a side note the overhead cabinet is a real biotch to put back in place w/o help.


*Correction. Vent temp 79.8 And rising

Ambient is around 90.
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85 Weekender w/ EJ22
Previously
64, 71, 72, 73, 76, 81, 84, 85 & 87 Campmobiles and Westfalias
and a 67 bug.

[dhaavers]

[AZ Landshaper]

Did that. Idle at 900
Pressures are. 40/195

Hanging in the gutter. Hatch as closed as possible w cover loosely fitted.
Friggin 91.2 at vent.

I’m thinking there’s air in there or some other contaminant. Would that account for decent pressures and ZERO frikkin cooling?

Re cabinet. Nice setup. If the cabinet comes down again I’ll be the new owner of those deals
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85 Weekender w/ EJ22
Previously
64, 71, 72, 73, 76, 81, 84, 85 & 87 Campmobiles and Westfalias
and a 67 bug.

[AZ Landshaper]

If I need to reduce on the low side do I just open the valve on the low side of the manifold and let some of this gas go or how is that exactly done?? I’ll be sure to have a smoke going while that goes down.
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85 Weekender w/ EJ22
Previously
64, 71, 72, 73, 76, 81, 84, 85 & 87 Campmobiles and Westfalias
and a 67 bug.

[Abscate]

Cycle the co press or off and see if the low side pressure climbs fairly quickly or if it stays stuck at 25-30 psi

I’m smelling the scent of plugged something on the low side, but my internet AC diagnostic Fu isn’t great
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[AZ Landshaper]

When I turn everything off the pressure jumps to 80 on the low side and drops to 100 on the high.

Honestly it’s gone from bad to worse. The pipe was getting cold and other getting real hot. Now. Just hot. Don’t feel but a whee bit of cooling at the low pressure side plumbing.
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85 Weekender w/ EJ22
Previously
64, 71, 72, 73, 76, 81, 84, 85 & 87 Campmobiles and Westfalias
and a 67 bug.

[khughes]

[MarkWard]

In all of the pictures, the high side pressures look a little low for a hot day, but If I had those pressures, I would expect the AC to be working better. I also don't have experience with Red Tek.

If you look at your gauges, the scales towards the center are temps. There is a correlation especially on the low side between the pressure and evap temp. I'm too lazy to read back. Did you put in a new expansion valve? To a point the early style is adjustable, but the system has to be open.

I'm resurrecting my AC and the replacement expansion valve is suited to 134. Its the H type though. Red Tek is supposed to be a magical gas that out performs everything. Problem is if you have to service your system, no one is going to have a recovery machine for Red Tek. So, I'd start with adding a little more before you let some out. You can always let it out.

[high-speed wobble]

Are you seeing low side 'hunting?' My system is entirely rebuilt and recharged with Red Tek also, but my low side fluctuates between say 22 and 30 PSI so I am thinking I may be undercharged. I've read that hunting can be caused by undercharge.

I like your setup dhaavers. I did a similar thing with a boat stand. That thing was the only reason I was able to do this on my own I think:

Anyway I'm with you in your troubles right now, AZ Landshaper. I get about a 22-25 degree temp drop from ambient with pressures around 27(~22-30)/225, charging at about 72F and testing between 65 and 75F. I'd like to see my vent temps lower than ~50F at 75F ambient for sure with hopes for keeping the kid cool when temps are in the 90s.
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1990 Westfalia, GW2.2, Peloquins TBD

[Farf]

[AZ Landshaper]

Theres no hunting. Its pretty solid. Not one lick of cooling occurring.

Pipe from the compressor is cool to touch but not cold.

The TXV seems to be working. The low is around 30-40 and the high 200-225 when the engine and compressor are off the system equalizes near 100.
TXV is not new and its not the H type. it was replaced by a PO who converted to 134.

Frustrating to say the least.

Unfortunately more than one person has contacted me to say I should ditch the red tek. One said he was never able to get temps below 65 and the other is a naysayer that thinks Ill be at an AC tech before the weekend and they wont touch it. Both have working AC in vanagons.

My concern is every time I need to recharge Ive got to send money to Tennessee and wait for a delivery. Ive used 4 cans of the stuff so far. Only one left.
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Support Small Business.

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85 Weekender w/ EJ22
Previously
64, 71, 72, 73, 76, 81, 84, 85 & 87 Campmobiles and Westfalias
and a 67 bug.

[high-speed wobble]

Farf, I've read a lot of your comments in the Red Tek thread. You seem knowledgeable about A/C systems like this, do you know whether the TEV hunting can cause damage elsewhere in the system? My compressor (and everything else) is brand new, and this seems like the sort of thing that could dump liquid into the suction. I'd like to do some higher-temperature testing but I don't want to cause damage.

I have the late model "H" type expansion valve, and no idea how begin with adjusting it. I hate giving my van over to shops but maybe this is one to consider hiring out. When I rebuilt my hoses, I moved both my service ports to the compressor fittings. Very glad I did that if I am looking at getting a tech to look at it.

AZ Landshaper, sorry to hear about your troubles. That seems like a difficult to diagnose problem since your pressures seem good. Very frustrating. If you end up at a shop, I wouldn't mind hearing what kind of performance you end up with.
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1990 Westfalia, GW2.2, Peloquins TBD

[Howesight]

Hi Landshaper:

1. Can you post some pics of your whole evaporator box assembly? It's hard to tell from your other pics (including your gallery) what your evaporator setup is. Mainly, I question whether your AC evaporator plenum is forcing all air through the evaporator or whether some ambient air is permitted to flow around the evaporator instead of through it.

2. Looking at the gauge pressures your posted in pics and the 90F degree ambient temps you mention, I think that your refrigerant fill is on the low side and you could usefully add some, provided that your AC compressor is not a variable-displacement design. If it is a variable-displacement design, (see below) then you might already have enough refrigerant in your system.

3. Also, could you post some pics, including the part numbers on your compressor? I think that you might have a variable-displacement compressor on your EJ-22 which would explain the relatively small changes in low-side pressure. If the variable-displacement control system is malfunctioning, that could explain why your system yields low-side pressures in a range that should yield a lot lower evaporator vert temps, but still fails to do so. Essentially, the low pressures at the low side, when the variable-displacement system is operating correctly (there are electronically-modulated versions and purely-pressure modulated systems) are the signal to the compressor, in the pressure-modulated versions) to increase the compressor's output

4. After the variable-displacement system reduces compressor flow, as described above, your TXV is only spitting out a tiny bit of liquid refrigerant into evaporator which instantly evaporates (you should feel a cold portion of the plumbing right after the TXV) and this is not sufficient to adequately cool the remainder of the evaporator. In essence, you might just have a malfunctioning TXV which malfunction is being hidden by the combination of the variable-displacement compressor and its operation. I say this because the pressures you show would, if there were no variable-displacement compressor, likely cause low-side pressures to be much lower than indicated as your compressor would suck the gaseous refrigerant and the high-side pressures would rise, as the compressor would be running at "maximum" displacement. Compressors without this feature run at maximum displacement at all times and address high-side over-pressure and low-side under-pressure by cycling the compressor clutch on and off.

Here is a link to an article on general diagnosis of problems in variable-displacement compressors: https://www.motor.com/magazine-summary/diagnosing-variable-displacement-compressors

Remember that the Vanagon evaporator is HUGE compared to modern vehicles and even compared to 1980's vehicles. It needs a large flow of refrigerant, especially when the evaporator is initially being chilled, to start to extract heat from the air flowing through it.
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'86 Syncro Westy SVX