confusing AC gauge readings

[NathanR]

Buck,

If you haven't read discseven's (Karl's) thread, he was introducing air when changing r134 cans. He switched to a 30 lb canister and had better results.

Good luck,
Nathan

[88911coupe]

Nathan, thanks for the suggestion. I did read that process, seemed like an ingenious solution. What I have been doing is letting the line purge a bit then hooking it up to the manifold to recharge. I guess I could be letting some in accidentally.

[wwest]

Originally Posted by NathanR

Buck,

If you haven't read discseven's (Karl's) thread, he was introducing air when changing r134 cans. He switched to a 30 lb canister and had better results.

Good luck,
Nathan

Just re-read the entire 100+ pages..

When first switched to the liquid fill using a 30lb jug he got the very same results. Thread got closed before any more results could be recorded. His final report shows the same "dither" level as before.

Plus a low charge, no way to know if a full charge, ~40 OZ(***), would have gotten him factory standard, +Kuehl, performance, no vent rise at idle.

*** 36 Oz for "standard" retrofit, + 4 OZ for Kuehl's Fender condenser/fan.



Maybe Kuehl's Spal fan stopped working again

[wwest]

Originally Posted by Bob Kontak

How many old 911's are running right now with only 12 oz of refrigerant in them with AC on and they are being drivin hard?

"Knowingly" driven with low charge.

Besides which I don't think many drivers would leave the A/C turned on producing no cooling as just happened to OP.

[Ronnie's.930]

Originally Posted by Bob Kontak

Stuff your missile school up your bum.

Imagine the level of snickering going on among the Army recruits in his "classes". And no doubt he was wondering to himself "wuts wiff all the giggles?".

[Pazuzu]

Originally Posted by Bob Kontak

Thanks for the direction.

I pulled out my beer gear and see it's a 1/4" tapered pipe thread in the regulator.

Are those tapered fittings on the AC gauge coming out the side? Looks like 1/8 tapered pipe? I may already have most all I need.

Let's drag this thread (kicking and screaming) back to a useful subject (that being, beer!)



Basic boring cheap single gauge regulator. They generally have 3-4 ports, and they are all standard, the same as your air chuck adapter threads (1/2 inch NPT??). Here you see a regulator, the adapter, then a cheap coiled airline.



Here is the regulator on a 10 pound tank, with the airline mounted.



And here is the 5 pound and 10 pound tank next to a mug o' beer. Now, you won't know what beer this is, but Ronnie does (Texan, spends all their cash on the p-car, drinking yellow beer when it's 103 degrees out...)

[wwest]

Originally Posted by Bob Kontak

Only the thousands who post about failed AC compressors because of low refrigerant charge. Like none - EVER.

Then you are basically saying the pressure switch low setting has proved to be useless?

Home run, Willy. God damn, you are one tactless, but at the very least stupid, 80 year old.

Stuff your missile school up your bum. You are a liar.

Oh, hey - prove me wrong. That's the new mantra. Correct until proven incorrect. It's Willy's law.

FOAD

Ignore wwest

I present ideas based on solid theory.. the response is "Like none - EVER".... With no explanation.

On the other hand might you be saying, concluding, that since no one has posted such a failure they don't exist..??

[wwest]

Post #1700.

Initial 34 Oz charge, 10 PSI "dither".

Boost to 36 Oz charge, lower "dither", 3 PSI, high side pressure UP, low side pressure DOWM, Vent temperature lower.

Why did he revert to 26 Oz?


My AC burns me up --- Help!

[Ronnie's.930]

Originally Posted by wwest

I present ideas based on solid theory.. the response is "Like none - EVER".... With no explanation.

On the other hand might you be saying, concluding, that since no one has posted such a failure they don't exist..??

Considering that azhodge didn't run his system without oil, wouldn't a further discussion about the horrors and general prevalence of doing so, as well as the merits of having a low pressure switch in place, be a candidate for a separate thread on the subject(s)?

[wwest]

Originally Posted by Bob Kontak

How many old 911's are running right now with only 12 oz of refrigerant in them with AC on and they are being drivin hard?

Deviation from OP subject matter began here...

Bob, start a separate thread?

[Pazuzu]

Originally Posted by Bob Kontak

Thanks for dragging.

That has to be Pearl unless Blue Bell makes beer now.

Spent quite a few years in Houston.

Ehem...Lone Star...ehem...

No one drinks Pearl anymore, it must have been in the 20's or 30's that you were out here!

[Ronnie's.930]

^^^ Exactly, Bob was already a teenager in the 1930s!

[tirwin]

Shiner Bock ain't bad t'either! And it's German style.

[88911coupe]

Well decided to try and add couple of cans after several hours pulling vacuum several times then letting car sit. After two cans saw 25 on low side and 275 on high side, keep in mind it was 105-106 today and about 100 when i added the r134. Took out for short test drive around the hood and it was relatively cool. Next temps got down to about 54 so nothing to get too excited about. My concern is adding r134 will start pushing up pressures...correct? Also, the compressor is making a lot of noise...thinking it may be going bad. It was smooth as glass when out but of course that was not pushing any pressure.

[tirwin]

100ºF ambient temp your high side should be 276psi with R134a according to the chart I am looking at.

How many oz in each can you're using?

Switching cans could be introducing air into the system. Maybe explain your method?

[88911coupe]

Yes, have been thinking of just springing for new compressor since they aren't very pricey. Have also thought about just picking up a 30 lb canister of r134...also not very pricey. As far as the process I use on the cans (12 oz each)...I close manifold gauges, then allow a bit of r134 to purge the hose then charge it by air. Not optimal I guess.
Both fans working fine.

[Ronnie's.930]

Originally Posted by Bob Kontak

You can just use my account name.

Gluteus Maximus Auto Fixemus is the name of yer shop, correct?!?!?!

[Ronnie's.930]

Buck, what kind of a noise is the compressor making? I've never heard them make noise, but I have replaced compressors when they've started leaking.

One benefit of the 30lb pound tank that spoils you right away is the simplicity and speed of using one (as opposed to the individual cans). . .

[wwest]

Originally Posted by 88911coupe

Well decided to try and add couple of cans after several hours pulling vacuum several times then letting car sit. After two cans saw 25 on low side and 275 on high side, keep in mind it was 105-106 today and about 100 when i added the r134. Took out for short test drive around the hood and it was relatively cool. Next temps got down to about 54 so nothing to get too excited about. My concern is adding r134 will start pushing up pressures...correct? Also, the compressor is making a lot of noise...thinking it may be going bad. It was smooth as glass when out but of course that was not pushing any pressure.

I don't pretend to understand why this seems to be the case but it appears that a low refrigerant charge results in high pressures on the high side.

The widely recommended R134a charge level for our Porsche's is 36 Oz, 75% of the factory r12 level. Possibly more like 40 Oz with extra condenser.

Worth a try..??

[tirwin]

Originally Posted by Bob Kontak

T-Rex Practical Auto Repair

"I've got a big head and little arms."