Hey Reid/WWEST. Why dont you give us the 3 sentence snapshot of how this post supports your theory and understanding of why its related to this discussion.

"He" is simply bored.
However, his personality, being narcissistic, means he will seldom if ever
listen or understand your reasoning, never mind agreeing with you.. lol.

Kuehl: TXV's designs used in the automotive industry never fully close.

Wwest: TXV's operate using "superheat" criteria to regulate the incoming flow of refrigerant, if that criteria should "dictate" a fully closed TXV then that is EXACTLY what will happen, what MUST happen in order to prevent damaging the compressor.

So when, under what circumstances might the superheat criteria dictate full closure of the valve seat?

At anytime there is not enough heat to fully vaporize, and slightly beyond, the refrigerant flowing into the evaporator.

1. Thermostatic switch at MAX but a blown evaporator blower motor fuse..

2. Not enough incoming warm airflow to prevent ice, INSULATING ICE, from forming on the evaporator cooling vane/fin surfaces.

Wwest you old rattlesnake....lol

:p :p :p

Strike a vein..??

Well, I read it and it doesn't support what wwest is saying.

And it certainly doesn't prove that the TEV closes all the way.

On the other hand if you can find ANYTHING that states that the TXV in our Porsche's doesn't fully close then I'm all ears...

Oh i get what you are saying and im not an idiot. we all need educated on what a TXV or TEV is and how it works.

But if ours doesnt close. and the article is based on one that does.. then that would make it fairly irrelevant. right?

thought so... bunch of smoke and mirrors.

smoke and mirrors.

post your video. it really is the answer to all your naysayers.
whether it closes is immaterial. really...

Has to be.

One has to wonder what goes through his mind when he launches a real "zinger"?

Let's talk superheat........

Why is superheat mentioned this late in the game?

I ran across the superheat concept - never heard of it before - just this morning while googling "Do Automotive expansion valves fully close"??

How can it be possible that a DIY (barely wanna-be) AC tech like me finds this information an hour before it's posted for reference but weeks after the issue surfaced?

But then doesn't the criteria for TXV superheat REQUIRE full closure if the conditions are met for such action..???

Ask Kuehl what prevents compressor slugging when the evaporator freezes up due to a maladjusted thermostatic control switch..?

the problem is that you determine your position, then attempt to prove it. often with toally unrelated material. and with a closed mind.

your video would prove it. that simple. what are you afraid of?

I dont disagree that "if" the conditions were met that this would make sense. But we are right back to the same thing then. are those conditions met? and are their other factors like physical design that could prevent what you say... I dont claim to be a subject matter expert on this stuff. but im sure you arent the first to ask and answer these questions.

Conventional wisdom vs experience vs speculation vs proof. Why dont you just shoot your video and prove to yourself whatever you are trying to prove...

Your statement "often totally unrelated material" would seem to indicate the lack of an "open-mind", unable (unwilling..??) to see the "parallels", on your part.

"..prove to myself...??

That event has long since passed. If the 120F to 155F temperature rise of the rear condensor wasn't enough (it was) then reading Kuehl's dessertation on non-barrier hoses and "extreme pressure" put the final nail in "that" coffin.

At this time the longer I delay doing the video the more time the naysayers have to learn on their own....Mom always told me "self schooling is the best you can get.."

Maybe that way there will be less questioning of the video results once I get around to it, August, maybe, in Memphis, even.

what question are you trying to answer?

What theory are you trying to prove?

You seem to be all over the board. changing the subject constantly to shift the argument. You also have a thread where you argue to the death that these hoses dont leak... now you are accepting as gospel that they do? which is it? why dont you test the hoses to see if they do? how hard would that be? rig up a video and test it. or are you now on the Kuehl wagon and are now going to change your hoses as he recommends? Whatever fits your argument of the day is the position you take. For two years you have said they dont leak. stating that Kuel is selling snake oil for saying they do. now you are agreeing with him, saying they do in fact leak.

On the more immediate theory... The increase in temp doesnt prove anything because you havent proven that the temp increase of 35 degrees = increases in pressure... and what does that have to do with whether the hoses leak by design or because of the R134a molecules... what is your theory?

So by shooting the video and doing the tests... you will indirectly prove whether the TXV / TEV is closed ... or not... which will allow you to test whether the pressure increase leads to pressures high enough to cause leakage? which will allow you you know whether a spal fan with a trinary switch will impact the underlying problem of refrigerant loss? and whether that leakage is in fact through hose design or some other mechanism? you are dancing... and you arent a very good dancer...

so you in fact have ALOT to prove... Wake up WWEST!

Kuehl states the TEV doesn't close. He's the professional here.

The only professional. wwest claiming it closes? Since his knowledge of the subject is suspect (obviously, from his writings) and his hypotheses require conditions that do not exist on these cars, I would suggest that burden of proof on this subject lies completely on wwest. When weighing evidence, one must look to the credibility of the person who is presenting the evidence as to how much weight that evidence is given. An AC professional? Or some guy on the internet? Reasonable people make the best choice most of the time. I consider myself reasonable, and I will take Kuehl's word over wwest's.

Unless wwest has documentation or photographic/video evidence of the part in question. Our cars have compressors that are thermostatically controlled. Therefore, a full-closed TEV is not necessary to protect the compressor from liquid slugging. And, IIRC, compressors don't do well if the low side gets close to vacuum. It's bad for them. So having the valve open at all times prevents a low-side pressure that's too low.

Seldom ever happens if 'ever' in a 911 or 930 because of the volume between the the expansion valve outlet the compressor inlet is so large; you have the evaporator and then 12 feet of #10 hose.

The expansion valve 'type' used in the 911/930 never closes all the way! :cool:
So, when a compressor is turned off the reed valves close and high side pressure does not migrate back to the TEV,
the system equalizes because the TEV does not completely close.