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High Line Pressure (please help ) <---because of user error :(

flynbrd on Mon July 19, 2010 11:31 AM User is offline

Year: 1990
Make: Ford
Model: Thunderbird
Engine Size: 3.8
Refrigerant Type: 134a
Ambient Temp: 100
Pressure Low: 40
Pressure High: 300
Country of Origin: United States

First what the system has

3 core brass radiator with taurus electric fan
134a conversion
New Parallel Flow condensor
New Liquid line with repair kit so I could install blue o
Reman Compressor but that was switched back to Factory unit
New Dryer

History
The car's ac started running high line pressure after I finally got it back on the road after years of sitting. The compressor uninstalled over that time but I had the discharged tube covered. When I put the system back together I replaced everything but the discharge tube and evap. The system will not take a fully charge, if you do use the full amount pressure will hit 550 on the high side 60 on the low. The original condensor was replaced with a new parallel flow which should improve my cooling over stock. I've tried 3 attempts so far to find the problem. On the last attempt I did the following, Flushed the evap 2 twice (I have a new unit to compare air flow, both units seem to flow about the same.) ,Flushed the condensor to be on the safe side, flushed all the lines. I drained every trace of oil in the system, there was a ton of left, plus the leak dye remaining in the system. Drained the compressor and dryer best I could. I put everything back together (added 5 ozs of pag 46 to compressor and turn it once installed before fire up) and filled the system to about 20ozs before the high side was hitting 300 and the low 40. Outside time was 101. The electric fan is working, infact you hand will bake if you leave it in the air flow for to long. Once the pressure hits above 25 psi on the low the compressor will not shut off. The pressure switch is new but I havent got a chance to adjust it since the system will not drop low enough. Before recharging the system I did evap for 1 hour. All the lines blow air so I assume no blockage. The car does blow cold about 60 I would say maybe 70.

Thoughts?

Edited: Thu July 22, 2010 at 12:33 AM by flynbrd

bohica2xo on Mon July 19, 2010 11:36 AM User is offline

Duct tape.

Put the gauges on it, and duct tape them to the windshield so you can read them while driving.

Post the pressures above 50mph.

B.

-------------------------
"Among the many misdeeds of the British rule in India, history will look upon the act of depriving a whole nation of arms, as the blackest."
~ Mahatma Gandhi, Gandhi, An Autobiography, M. K. Gandhi, page 446.

flynbrd on Mon July 19, 2010 2:58 PM User is offline

I spoke with company that sold me the parallel flow condensor. According to them the whole system should require less 143a course he didn't say how much. I'll bleed the system down to 35low and the high should be about 265.. Hmm I guess the best approach would be to set a temp gauge in vents then bleed freon till I find the sweet spot. I just find it hard to believe this system now runs with 20oz or less of freon... I'll take the car for a drive with the guages hooked up and let you know the results.

Thanks

TRB on Mon July 19, 2010 6:02 PM User is offlineView users profile

Thought the purpose of having a condenser that would handle the heat load was so one could charge close to OEM specs.

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iceman2555 on Mon July 19, 2010 6:27 PM User is offlineView users profile

Will you please post a photo of your new condenser. Not a picture from a web site...but the actual condenser in your vehicle.
Last week, encountered a problem with a late model vehicle in the Phoenix area....new compressor...new condenser...the works....high side pressure out the...well you know the expression. Proper charge rate...swear on what ever...the charge rate is right on.....it was....all was great...except the NEW PFHE condenser was a brass and copper large tube serp type condenser....so...would like to see your unit.
On this vehicle...are you measuring high side (liquid) or high side discharge (gas)? Is the service port before the condenser inlet (between the compressor and condenser) or in the liquid line after the condenser?
This system should hold a full charge of 134a and not blink an eye. Seems as if something is rotten in Denmark....or what ever the hell it was I learned in school.
How are you determining the amount of refrigerant in the system?
I know this sounds like a very stupid question...but is the fan blowing in the correct direction? Yep, have seen them going the wrong way on a one way street.
Not sure why the change to the liquid line repair kit....the correct orifice would have been installed in the liquid line to begin with. A severe restriction (reduced orifice tube size) could produce a restriction...but doubtful it would be enough to see pressures exceed 550...damn good set of gauges by the way.
What type flush chemical was used? This could be very important!
Let us know a bit more.

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The strongest reason for the people to retain the right to keep and bear arms is, as a last resort, to protect themselves against tyranny in government.
Thomas Jefferson

TRB on Mon July 19, 2010 6:34 PM User is offlineView users profile

Quote
Originally posted by: iceman2555
..except the NEW PFHE condenser was a brass and copper large tube serp type condenser....so...would like to see your unit.

Ice a few are passing off these types of condensers as PF. Which they are if strictly related to the flow of refrigerant. That's why I've been saying multi pass multi passage condenser these days. Even using a different phrase does not help clear the air on this issue.



-------------------------
When considering your next auto A/C purchase, please consider the site that supports you: ACkits.com
Contact: ACKits.com


Edited: Mon July 19, 2010 at 7:03 PM by TRB

iceman2555 on Mon July 19, 2010 6:59 PM User is offlineView users profile

Totally understandable.....the major problem with this event....the 'tech' (???????) had already installed four new compressors......replaced them because....get this....'they were making too much pressure......" It is beyond me...how a person can call himself a professional tech and make a statement like that.....it just simply drives me bonkers. However, it seems each day this statement seems to creep in.....how can one repair an AC system when there is no knowledge of how the damn thing functions? Each day, I think I have heard the best....but each day brings another.....still think the book is a great idea......!!
And the next time I hear....'they are a good shop....all the techs are ASE certified....and KNOW what they are doing.....!!!!! My response is going to be...'well, if they are so 'bleeping' smart...why can't they fix the damn thing????? The art...no art is not the correct word....the KNOWLEDGE of diagnosis a system is rapidly becoming lost....hell...just throw another part on it....see if this one works......!!!!
With the economy in such shambles...we are seeing more and more dealers calling jobbers for parts. Not sure if this is a good thing or not...but what the heck...parts is parts...right.
Anywho....talked to a service manage...a Chrysler dealer....he actually stated that he expected to have to replace three compressor prior to obtaining one that would actually work.......once more....one would have to hear a recording of these calls to believe......my book would have to be considered 'fiction' for sure.

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The strongest reason for the people to retain the right to keep and bear arms is, as a last resort, to protect themselves against tyranny in government.
Thomas Jefferson

flynbrd on Tue July 20, 2010 10:10 AM User is offline

ok the numbers are in.... Good and Bad, outside temp was around 101-102

The good -At startup the low side was 30 and the high 270ish
The bad- The low was 40 and high 300 yesterday... it held vac so I'm hoping no leak

The car at idle with 30 low and 270 high was running 11c / 51 fah. at the vent max ac
The car quick run at 45 mph kept the low around 30 and the high dropped to 250ish range maybe 260 its was hard to tell. guage barely reached the windshield, but I did see the high side drop some. Vent temp was 8c /46 fah.

Thoughts

If the freon truly leaked out I would say the system requires a lot less freon to work... Tomorrow I'll place the guages back on and see if it dropped any. Also I might take some number readings off the condensor to see how much of a temp drop I'm getting.

bohica2xo on Tue July 20, 2010 11:41 AM User is offline

Obviously some condensor issues there.

FoxBirds are not the best candidate for a conversion. It takes a good PF condensor, and a clean install to make sure no air bypasses the condensor.

Electric fans are hit & miss. Your statement about how hot the air from the fan is tells me that the airflow is too low. If you were moving more air, the temp would be lower. Even though some models of Taurus were 3.8's, the heat exchangers were much better packaged than the Fox platform. If you took the whole Taurus heat exchanger package, radiator support & all - and stuffed it in the nose of the Fox it would probably work ok - unless it came from a 3.0

Usually a road test shows up a poor fan quickly. Your system was still showing high pressures @ 45 mph, and at a reduced charge. I agree with Ice, I would like to see a picture of this condensor & install. Even a the OEM tube & fin will do better than that if the car is moving.

B.

-------------------------
"Among the many misdeeds of the British rule in India, history will look upon the act of depriving a whole nation of arms, as the blackest."
~ Mahatma Gandhi, Gandhi, An Autobiography, M. K. Gandhi, page 446.

JeremyB on Tue July 20, 2010 5:13 PM User is offline

Quote
Originally posted by: bohica2xo
FoxBirds are not the best candidate for a conversion. It takes a good PF condensor, and a clean install to make sure no air bypasses the condensor.

He's got an MN12 'bird. Foxes quit after 1988.

Aftermarket condensers are Piccolo, so hey may have one of those. Not sure what came OEM.

bohica2xo on Tue July 20, 2010 8:53 PM User is offline

Oh allright, an MN12. Still the unibody mushbang platform, and just a new name for the fox.

Still a poor candidate for a 134a conversion too.

B.

-------------------------
"Among the many misdeeds of the British rule in India, history will look upon the act of depriving a whole nation of arms, as the blackest."
~ Mahatma Gandhi, Gandhi, An Autobiography, M. K. Gandhi, page 446.

flynbrd on Thu July 22, 2010 12:54 AM User is offline

Ok I would like to thank everyone for the help on this issue... Now feel free to pull out your bats and goto work on my skull. The guage set I bought is really nice and setup for original for industrial a/c systems. No biggie right, well wrong , because I'm still new to this I thought the 134a scale I was using (which is right outside the r12) was the right one for readings.. WRONG! I took a closer look today after seeing a tubeyou video describing the scales on the guage, turns out there is no 134a scale on the set. Just Psi,r12,r22, r-502. So using the robinair conversion chart.
PSIG High reading 305 you get the following numbers gives my 134a high now 161
R-12 172
R-22 133
R-134a 161
R-408A 125
R-410A 97
R-502 127

So great and here I thought I was over charging the system..... These are the number I should be hunting for.
PSIG Low reading 26-30 which will give 134a reading 30-35
PSIG High reading 405-500 which will give 134a reading 182-505

The only questions I have is what would give a really high low side number? Sign the pump is failing? For example my 134a low is reading 60 and my high is 200..(yes measured in 134a scale)

btw the chart link


chart

Thanks

HECAT on Fri July 23, 2010 6:43 AM User is offline

Don't worry about or get yourself confused by the pressure/temperature relationship charts; these are engineering specs used for mathematical calculations. Trying to recalculate figures just gives us bogus info. Just read the true PSI, it is usually the outer ring in black.

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