A/C now not so cool - '90 Westy

[AtlasShrugged]

Without knowing what the high side pressures are..The OP did not say...everything is a shot in the dark. We know the low side was 35-45psi..but the high side psi will be helpful to know.

[RBEmerson]

~160-170 PSI and somewhat higher after overcharging.
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Lord, give me coffee to change the things I can change, and wine to accept the things I can't change.

[AtlasShrugged]

Okay so we are at 160-170 over 35-45 for pressures..at idle?

Front condenser fan coming on? Yes, If so..

What are the hi side/low side pressures if you rev the engine to 2000 rpm and hold it there for a minute? Are the pressures stable?

[RBEmerson]

Yes, the fan comes as expected.

I've forgotten the pressures. The system is now empty, ruling out checking that at the moment. The R12A shipment is due the middle of next week.
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Lord, give me coffee to change the things I can change, and wine to accept the things I can't change.

[djkeev]

[Howesight]

[RBEmerson]

Empty = 2.5 hours tied to a 2.5 CFM vacuum pump than can pull to 75 microns.

The drier sight glass still has a green not yellow ring.
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Lord, give me coffee to change the things I can change, and wine to accept the things I can't change.

[RBEmerson]

The system has been recharged and is currently holding about 38 PSI on the low side. The previously reported oscillating needle has stopped. The high side is holding at about 150 PSI. This evening I checked the vent temperature and got down to 50F or slightly less. The ambient temperature was 70F or less, so this isn't a real test. We'll see what happens tomorrow, with temps in the 80's and full sun.

The big change in this recharge is spraying the radiator and condenser with water from a garden hose. This dropped high side readings by 30-40 PSI. I started the job without the hose and saw the pressure hitting 180+ - Not Good. Using the hose dropped the pressure like a rock.

I'll retract my comments about fractionating. Red Tek says this not a problem. When venting, they do say that the discharge has oil mixed into it. That's a real fire hazard.
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Lord, give me coffee to change the things I can change, and wine to accept the things I can't change.

[Terry Kay]

Why is it an issue to run a box fan on the condensor as your loading the system up?

38 psi is too high, 150 is too low.

I didn't know , haven't ever seen a water cooled condensor on any vehicle--never.

Your taking your own path here again in getting this thing up & running and it ain't right.
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T.K.

[RBEmerson]

Sigh... I knew you'd say that.

On the pressures, I am certain that you know far more about Red Tek than the tech support people at Thermofluid Technologies. I'll be sure to tell them how in error they are.

Spraying 60F water works. It beats blowing low speed ambient air, already hot, at the condenser.

The air conditioning in my Vanagon is doing a good job regardless of your naysaying. Get over yourself.
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Lord, give me coffee to change the things I can change, and wine to accept the things I can't change.

[Terry Kay]

Your 100% correct on all counts.
It's about time you discovered that.

Plunder away--which obviously is nothing new to you.
You're the guy that's been on this job for 2 years, and still haven't moved an inch, and more than likely will be on it for another 2 or 3 at this pace.
Not me--

Who in the hell said low air speed on the box fan?
You did--and again you're still on your own failure rate program here--don't change anything.

And at 90 degrees in Johnstown PA. you have lower ambient air temps blowing into the condenser at highway speed?
Oh--I see--you have a water tank on the roof blowing cool water on the condenser while on the roll to get better vent temps--
For sure you don't have any inkling on how to follow instructions--gathered here, or in any AC manual.

Bravo.
You have just won the the First Alfred E. Neuman award-
You ain't worried about anything--that's pretty plain & simple.
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T.K.

[AtlasShrugged]

[RBEmerson]

Referring to Thermoflluid Technologies (TT - the company name vs. product name), 180 PSI is definitely the upper boundary when charging the system. 40 PSI is acceptable in hot weather. Temps here will be in the lower 80's, so I'll shade my sense of "that's enough" accordingly.

Yesterday, while doing the top-off charge, temps were well into the 80's and the drive was throwing up heat from the sunlight. At a guess, I'd say the temperature at the condenser was well into the 90's. The box fan moves a lot of air but the high speed still isn't all that fast - maybe 15-20 MPH at best? As a seat of the pants test, it'll blow leaves around but won't raise dust. 20 MPH is, therefore, probably generous. (Google on reading wind speeds by eyeball). Anyway, blowing 85-90F air, while trying to dial in the charge, doesn't strike me as a winner. Farf (username) suggested misting and I agree with him that it's a good way to make the condenser think ambient temps are lower.

Reality says that on the road, it's easy to get stuck in traffic, with really hot pavement and hot air. Obviously pressures will rise accordingly. For now, however, I want to be close to "friendly" conditions, as per TT's tech support.

I've been reading vent temperatures all along. I agree that reading cabin temps will be misleading at best. The only subjective test I use is during a test drive: if the air's uncomfortably cold on my neck (it happens), things can't be too far off. But the data that objectively says what's happening is vent temperature. BTW, I have two thermometers, a standard a/c tech mechanical thermometer, and a digital kitchen thermometer. They agree within a degree or two; either they're both off (unlikely) or I've got good data (likely).

I've got a 45 minute "real world" drive (mostly Interstate) this morning. That should tell me more. If the weather forecast is to be believed, the return trip should be in full sun and 80F+. If the vent temp holds as expected, "movie over". Time to bolt the cover back over the high port.

More later.
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Lord, give me coffee to change the things I can change, and wine to accept the things I can't change.

[AtlasShrugged]

I would agree 180psi is the upper level When Charging the System...for sure.

Operational pressures are a different story and the high side will move around to higher than 180psi depending on conditions.

The box fan is an additional airflow..even if it not much..everything helps in testing. Don't over think the testing.

Pressures at 2000rpm..with even a 10mph box fan air flow on the front of the Vanagon...the readings are important.

Sweating suction line? That tells a story too.

[RBEmerson]

Now showing 46F on both thermometers. Mission accomplished. Out.
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Lord, give me coffee to change the things I can change, and wine to accept the things I can't change.

[dhaavers]

Nice work.

I went the same approach (hose spraying condensor) when I was having trouble
dialing in pressures this spring. Eventually settled in at 39° at the vents.

Ultimately you gotta go with what's working.

Keep cool!

- Dave
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86 White Wolfsburg Westy Weekender
"The WonderVan"
<EDITED TO PROTECT INNOCENT PIXELS>

[Terry Kay]

Link

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T.K.

[dhaavers]

^^^ Or else some minor, unknown, random, single-or-combination of issues with
his/mine/our AC systems that's a shot-in-the-dark to diagnose over the internets...???

Pick one or more:
- not-quite-perfectly clean system, even after DIY flush...
- not-quite-fully-evacuated system before charging, resulting in...
- slight latent moisture in system...
- slightly marginal compressor...
- slightly blocked exp. valve...
- more-or-less-effective blower fan while charging...
- anywhere from perfect to marginal gauge set...
- others...(make up your own, it's fun!)...

Any one of these conditions will display a particular symptom and point to a likely
cause, but a combination can certainly make it challenging to narrow down, right?

Despite all our internet buddies, we're ultimately all on our own out here in DIY-land,
and any of us may or may not have the time/interest/budget to "do-over" a job until
it comes out like the textbook suggests...

PS: Seriously though, and ranting aside, thanks for your helpful input over the years, TK.

- Dave
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86 White Wolfsburg Westy Weekender
"The WonderVan"
<EDITED TO PROTECT INNOCENT PIXELS>

[whynotvw]

Certain things are best for the pros. Even most repair shops don't like to mess with A/C systems. I would take it to the A/C specialist. They have all the right tools to diagnose the problems. No need to guess and spend countless hours.

I had some issues and took it to A/C specialist and it took them less them 20 min to figure out what was wrong with the system. By the way, check with Yelp for good reviews.

[Ahwahnee]