A/C pressure monitoring

[VisPacem]

Howdy

I am and have been concerned with air conditioner issues and judging by the abundance of posts I have company.

Now I know nothing or next to nothing about A/Cs. All I know is I want it cold.
However reading the numerous expert responses to the inquiries, for which I thank the posters who are and have been so helpful in getting my A/C cold, I have noticed that a crucial point is the pressures on the low and high sides.
Pressure.
When as a good boy I did the Soviet of the People mandated 134a conversion on my wife's car, from the R12, being ignorant and obedient to Big Comrade who loves us so much, I did not use the Red Tek type gases.

Well, the system which was running nice and cold on R12 started leaking like a sieve and to make things even better eventually ruin my brand new compressor. Only too late a overload/release (?) valve was added which only had the effect to make me recharge my system every three days
De Profundis A/C vulgaris germanicus

Even with the Red Tek type gases the system never revived.

Spasibo Tovarich

To make a long story shorter, as the pressures seems the important point in a functioning system, is it possible or do the tools even exist to install a pressure gauge, to monitor I would say at least the high pressure side, in the dash so that in case of a visible alarming climb of pressure one could turn the A/C off and save his/her system.

Should I not be dreaming after my conversation with Jack Daniel and taking into account that I know nothing about A/C system, is it possible or realistic or ?

Please have mercy on a poor soul and save for yourself the comments such as how will you monitor it. is your vision that good, why would you want another hole /gauge in your dash or why do you want a cold A/C , why do you like sushi ?

Thanks in advance
_________________
LG aka VisPacemPB, *The* party Pooper

No Regrets (Nothing to do with Vanagons)

[Terry Kay]

Most all current automotive AC units( since the late 50's anyway) have a low pressure cut off switch.

If you ( think ) have fried your compressor, the low pressure switch has been removed, bypassed, or isn't working.

I have never seen , nor heard of an inline AC pressure monitering device.
If when you evacuate the system it holds the vacuum, your good to go.

And that's all there is.

What the problem is here with a basicly simple refridgeration system, is a lack of understanding what does what and when it gets done.

I've suggested many times getting ahold of the easiest place to learn basic automotive AC principles, the Mitchell's training & service manual.

This is where I learned a long time ago when I went to GM AC school.
At the door the instructor handed out the Mitchell Manual, so the students had a reference book to follow, and reference to.

What most of the folks here have is a word of mouth situation with no basic understanding of what's going on.

And this is the biggest problem.

You can't follow the game without a program.
_________________
T.K.

[FNGRUVN]

Hey VisPacem,

Along the same lines as TK said, your van('89) has a combination high/low pressure switch behind the D pillar cover. It will/should turn the compressor off if you lose pressure(blown hose) or if the pressure is too high(restriction). There really isn't a need to monitor the system.

Sorry, I know this isn't what you wanted to hear.
_________________
"Democracy is two wolves and a lamb voting on what to have for lunch. Liberty is a well-armed lamb contesting the vote." - Benjamin Franklin

[VisPacem]

[Terry Kay]

Interesting.

Most vehicles have idiot lights--no gauges to confuse folks.
And when the lights start blinking it's all over anyway.
Most folks don't watch the dash--

Just let me ask you this one---for grins.

Your not thinking of installing a AC auxillary high side pressure gauge in the dash in a Vanagon?

Your going to add another 15' of high presure line to the dash so you can moniter the AC system?

Two things will tell you when the gas is gone without a gauge.
(A) If the sytem has freon, you'll hear the compressor clutch kick on.
If it has no gas--it won't kick on.
If the vents are blowing hot air in more than a minute being on--your outa gas.

Simple, easy, not complicated, and fast.

You don't need more hose than you already have, and I sure wouldn't want to be adding any more then the 30 feet you already have.

Just another place to leak.

If it was a good idea--somebody would have done it a long, long time ago--
JC Whitney would have offered it back in the 50's, to get you another 10% + enonomy, along with the curb feeler's and the Hula Girl's.
_________________
T.K.

[VisPacem]

[Terry Kay]

All's I'm trying to say is why complicate a already complicated issue?

There are more's ways to skin that one cat, rather than buying another cat.

The AC is ususally one of three ways.
working, not working or blowing half cold.

Let's say you hooked up this gauge.

What's it really gonna do?

The low pressure switch will kick the compressor off before the compressor self detructs ---

And even if it didn't have any freon in it, it wouldn't blow up or lock up,because the oil that's in the lower end of the compressor will lubricate it.

( If you have any oil in it)

A better safety item would be to rig up an oil pressure gauge for the compressor.

This could keep you on top of the compressor lubrication situation , which is much more critical than how much freon is in the system.
_________________
T.K.

[VisPacem]

[FNGRUVN]

TK made a lot of sense, but if you wanted to monitor the pressures without adding any more hoses, you could use electric pressure gauges. You would have to get creative with some fittings. You could hook them up right at the compressor.

I wonder if your wife's car had all the old mineral oil removed? Or the high pressure switch is defective. This would allow the clutch to remain engaged while the pressures climbed to the point where the compressor couldn't do any more and would lock up. I suppose another theory could be that liquid is entering the compressor and causing liquid-lock.
_________________
"Democracy is two wolves and a lamb voting on what to have for lunch. Liberty is a well-armed lamb contesting the vote." - Benjamin Franklin

[Terry Kay]

So,
It wasn't the lack of freon , it was too much, then it lost it all at some pressure release valve behind the compresor. and then the compressor locked up, or blew up.

Well, here's thought on the multiple explosions & compressor failure's.

Each time you had problem's , you changed the expansion valve & the dryer along with the compressor--right?

If not--it wasn't the 134 that caused the problem, it be a "Flo" problem from the schrapnel left floating in the system.

You flushed the garbage outa system out each time the compressor hand grenaded too--right?

What was starting to sound like a mineral oil etser, pag non- compatibility problem now is starting to sound like a installation proceedure Boo-Boo.

If you missed the expansion valve and the capillary tube got plugged up, here's your high pressure build up, after loading it up with the 134.

Somebody filled it up, and the gauges should have told you this right away--unless of course the freon was installed using just a Wally World low pressure side gauge--which would have you zip about the hight side pressure fluctuations.

If the dryer got loaded up with a bunch of crap--
This will restrict the freon flow and raise operating pressure's.

Again, this would have shown up at the freon load up on the manifold & gauges.

Anything could have happened internally if the system wasn't washed out real good each time the compressor took a crap.

I think that the failure was a installation, & proceedure problem not a gas initiated lock up.

I mean, the gas could have locked it up, but something else caused the failure.

And why did BOTH high & low pressure cut out switches just happen to fail at the same time?

I'd be doing some serious Sherlock Holmes , Pink Panther investigating & repair's here rather than trying to buid better boomarang, & adding gauges & hoses & wires , Oh My.

Something ain't right.
_________________
T.K.

[Alan Brase]

[Terry Kay]

<<Ya think?>>

Getting close here Albert.

<< Actually there is a high side gauge. Right next to the low side gauge on the technician's gauge set.>>

Yea--on a AC Tech / mechanic's gauge set there is.

However, most folks won't take the AC tool plunge and bother to purchase the right stuff.
They'll stop at the end cap at Wally world where the 134 is located, and grab one of them _"instant gratification" jippo low prsssure only gauges, and they are good to go.

Happens all the time.

<<Sounds like the expansion valve and dryer were not changed nor was the system flushed of debris. Possibly even the old oil was not changed out with the R134 changeover.>>
10-4

<<I'd rather expect some very high tech vehicles DO have compressor monitoring gauges. 747's probably do. 777's probably have monitoring that the pilot only sees when there begins to be a trend towards trouble.>>

Problem is here in the real world we ain;t high tech in a Vanagon,Type 2, or whatever else we're driving.

Maybe a DC-3 Gooney Bird, Bamboo Bomber, or a Stearman PT-17 would be closer comparison.

Run by the seat of your pants.


<<Sorta like an idiot light?>>

The idiot is on the other side of that light.
Ya gotta just look at it once in awhile.

<<Square hula hoops. Do a patent search. Become another Wham-O.>>

Sounds more like Bab-O was in the lines,fittings, & compressor.
_________________
T.K.

[MarkWard]

It would be a lot of work to completely flush/clean an AC system on a Vanagon after a compressor came apart. Do a search on AC Black Death. Second, while I did get slammed for not taking the time to learn about Red Tek, There is a relationship between Evaporator Temperature and low side pressure. While it is important to monitor the high pressure, I always am more interested in the low pressure when troubleshooting a poor cooling problem.

I did take the time to go to Red Tek's website after my lashing here and read some of the information. It sounds almost too good to be true. They also have some other interesting products. I did not see if Red Tek is D.O.T. approved. I also did not read anything about flamability. When the time comes to add AC to my Vanagon, I will investigate the Red Tek some more. Looks like I need to refabricate my R/S engine mount and carrier bar to make room for the compressor and lines. Regards
_________________
☮️

[?Waldo?]

Red Tek is flammable.

[Alan Brase]