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Is V5 Refergerent Control Valve(RCY) Working?

pf24 on Wed June 11, 2008 12:39 AM User is offline

Year: 1997
Make: Pontiac
Model: Bonneville
Engine Size: 3.8
Refrigerant Type: R134
Ambient Temp: 60-85
Pressure Low: 30
Country of Origin: United States

On an early post I had said that I had installed a brand new compressor that did not bring the pressure down below 65 on the low side and produced no cooling.
I had thought I fixed the problem by tapping on the outside of the referegerent control valve (RCV).

I took low side readings over a couple of days. It is always 30 PSIG and steady and the discharge air in the car is exactly 50*F. This was taken at night at 60*F, and in the day at 85*F. The 30 PSIG and 50*F dischage air never seam to change, even when I speed up the engine.

Does this sound ok. I had wanted to get colder air. How does the RCV work? Could it still be bad? Any way to test?

I know I have exactly the right charge because I added it by weight.


Thanks

GM Tech on Wed June 11, 2008 7:49 AM User is offline

What is the high side (discharge) pressure? that will help tell the story. I'd buy or rent or borrow a gage set before I condemned the compressor......

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The number one A/C diagnostic tool there is- is to know how much refrigerant is in the system- this can only be done by recovering and weighing the refrigerant!!
Just a thought.... 65% of A/C failures in my 3200 car diagnostic database (GM vehicles) are due to loss of refrigerant due to a leak......

mk378 on Wed June 11, 2008 12:22 PM User is offline

If it's not working as well now than it did after you first got it going, may have a leak and lost some refrigerant. Reading only the low side pressure tells very little, especially with a variable compressor.

HappyHarry on Wed June 11, 2008 1:05 PM User is offline

Quote
Originally posted by: GM Tech
What is the high side (discharge) pressure? that will help tell the story. I'd buy or rent or borrow a gage set before I condemned the compressor......

I have a question regarding a discharge hose that just pop that goes from the back of the compressor on my 89 Buick Riv. I had a ASE mechanic who does all my work just retro my R12 to 134a an hour ago. He first evac the system, did a pressure test and all was OK. However when I was there he said for me to start the car and turn the AC on coldest AFTER HE CHARGED IT WITH THE REFRIGERANT AND OIL ON THE HIGH SIDE. I told him (Since I use to be a new car dealer years ago) "Hey Vinny why are you putting it in on the high side and he explained his reasons. When I started the car it was running and blowing cold air. By the way this system was completely redone 400 miles ago with R12 3 years ago. The car looks brand new and only 71,000 miles on it. Could what he did contribute to blowing the hose out. The hose looks new and he said he only had 250 lbs of pressure on that side and the hose should handle 600. I do not want to argue with him. If you can give me an answer that would be great and if you know the best place to get for the 89 Riv 3.8 engine the AC suction discharge hose that runs from the back of the compressor that I do not want to have made up and prefer a factory hose that would be appreciated. Buick Parts did not have nor 5 dealers.

Sorry to interupt your chat. I could use your help. Thanks.

HappyHarry

GM Tech on Wed June 11, 2008 1:31 PM User is offline

Your mechanic charged it exactly as I do-- put it all in on the high side--- this is also the assembly plant method of charging- anyone with an a/c service machine does it this way-- it is absolutely proper and correct- and best way..

Your hose was weak- probably due to heat- either find one aftermarket, or have the bad spot spliced and repaired- it most likely is blistered in that area next to a heat source- like exhaust manifold or the like.

Just looked- Napaonline.com shows your hose assembly

A/C Hose Assy





Click on image to see enlarged view



Item#: TEM200817



Attributes:
Descriptionischarge & Suction Line
Additional Contentsose Assembly & (1)-407008
(1)-407012
(2)-407122 O-Rings



-------------------------
The number one A/C diagnostic tool there is- is to know how much refrigerant is in the system- this can only be done by recovering and weighing the refrigerant!!
Just a thought.... 65% of A/C failures in my 3200 car diagnostic database (GM vehicles) are due to loss of refrigerant due to a leak......

Edited: Wed June 11, 2008 at 1:34 PM by GM Tech

mk378 on Wed June 11, 2008 2:02 PM User is offline

The system should have a high pressure cutoff switch, sometimes those need to be added when converting. The idea is the switch will shut down the compressor should the pressure exceed about 450 psi for any reason. If there is a switch in the back end of the compressor near where the hoses go you already have one and it probably was just a weak hose. Systems converted to R-134a do usually end up running at a somewhat higher pressure than R-12.

bearing01 on Wed June 11, 2008 4:42 PM User is offline

Quote
Originally posted by: GM Tech
Your mechanic charged it exactly as I do-- put it all in on the high side--- this is also the assembly plant method of charging- anyone with an a/c service machine does it this way-- it is absolutely proper and correct- and best way..

GM Tech,
Correct me if I'm wrong, It's probably considered the best way because most of the liquid refrigerant will end up in the condenser (and receiver-drier if a TXV system) rather than in the evaporator. That way when you do turn on the compressor it won't get slugged by liquid refrigerant.

I'm interested to learn a bit more about this technique. I don't imagine the car's compressor is running during the charge procedure. I would think that as soon as the liquid refrigerant begins to pool in the condenser (and drier) the saturation pressure of the system would equal that of the refrigerant bottle. This would cause the flow of charge into the AC system to stop. What does the a/c service machine do to force feed more refrigerant into the system? Does it have its own built-in compressor? Does it heat the bottle of refrigerant?

When I charge through the manifold gauge I first charge through the high side until the pressures equalize with the refrigerant bottle, also watching that the low side too gradually fills from the high side. Then close the high side hand valve and start the AC compressor to finish filling via the low side hand valve.

Chick on Wed June 11, 2008 7:02 PM User is offlineView users profile

Quote
Originally posted by: bearing01
Quote
Originally posted by: GM Tech
Your mechanic charged it exactly as I do-- put it all in on the high side--- this is also the assembly plant method of charging- anyone with an a/c service machine does it this way-- it is absolutely proper and correct- and best way..



GM Tech,

Correct me if I'm wrong, It's probably considered the best way because most of the liquid refrigerant will end up in the condenser (and receiver-drier if a TXV system) rather than in the evaporator. That way when you do turn on the compressor it won't get slugged by liquid refrigerant.



I'm interested to learn a bit more about this technique. I don't imagine the car's compressor is running during the charge procedure. I would think that as soon as the liquid refrigerant begins to pool in the condenser (and drier) the saturation pressure of the system would equal that of the refrigerant bottle. This would cause the flow of charge into the AC system to stop. What does the a/c service machine do to force feed more refrigerant into the system? Does it have its own built-in compressor? Does it heat the bottle of refrigerant?



When I charge through the manifold gauge I first charge through the high side until the pressures equalize with the refrigerant bottle, also watching that the low side too gradually fills from the high side. Then close the high side hand valve and start the AC compressor to finish filling via the low side hand valve.

It is the best way, but not recommended for DIY'ers, just because of what you said or asked, should the car be running. NEVER charge thru the high side with the compressor running.. Compressor off, let the vacuum pull in as much as it can as liquid thru the high side, if not fully charged (no machine) then finish with the compressor running, high side gauge closed and vapor thru the low side.. Experienced techs can also charge liquid thru the low side, "slowley"... Hope this helps..

-------------------------
Chick
Email: Chick

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Freedoms just another word for nothing left to lose

pf24 on Wed June 11, 2008 7:40 PM User is offline

pf24 on Wed June 11, 2008 7:44 PM User is offline

Hello again,

I had pressures taken again today.

Ambient Temp: 67*F 70% relative humidity

At Idle LS=34 HS=175

AT 1500 RPM LS=29 HS= 235

Disharge air in the car 50*F and steady


Is the low side suspose to be lower? Does this sound like a bad RCV valve in the new V5 comprssor?


Thanks,

Peter

TRB on Wed June 11, 2008 8:39 PM User is offlineView users profile

Compressor Type Harrison V5 5-Cyl.
System Oil Capacity 8 ozs.
Refrigerant (R-134a) Capacity 32 ozs.
System Operating Pressures
High Side 185-245 psi
Low Side 29-37 psi

Approximate operating pressures at 80°F (27°C) and humidity at 40 percent or more.

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

pf24 on Wed June 11, 2008 9:14 PM User is offline

Thanks for the info.

Should it be colder or is 50*F normal for a Harrison V5 system in a bonneville?

TRB on Wed June 11, 2008 10:26 PM User is offlineView users profile

Ambient Temp. °F (°C) (1) Outlet Vent Temp. °F (°C)
60-70 (16-21) 42-50 (6-10)
80 (27) 47-57 (8-14)
90 (32) 53-63 (12-17)
100 (38) 55-65 (13-18)
110 (43) 60-70 (16-21)

-------------------------

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

GM Tech on Wed June 11, 2008 11:26 PM User is offline

My recovery machine warms the refrigerant as it recycles it - cleans it and extracts any air in tank-- so I can charge a system with double or triple the specified amount- if I wanted to- right into the condenser-- my machine does not pump it in- no need to when the refrigerant is warmed and it jumps right in the system in about 20 seconds-- this is a big advantage of having a service machine-- and of course the engine is off while I'm doing this-- I then start ithe car- then open the suction valve on machine- close the high side valve on my machine- so it sucks in the remaining charge in the hoses- then I close the port valve on the high side- and open the high side valve on my machine- so it sucks all the high side hose down as well and into the car-- then since my high side now reads the same as suction I can safely disconnect the high side port with little or no spatter- then I unhook the low side port valve-- then I suck the remaining hose refigerant back into my machine so the gages read zero for the next car....

-------------------------
The number one A/C diagnostic tool there is- is to know how much refrigerant is in the system- this can only be done by recovering and weighing the refrigerant!!
Just a thought.... 65% of A/C failures in my 3200 car diagnostic database (GM vehicles) are due to loss of refrigerant due to a leak......

pf24 on Wed June 11, 2008 11:31 PM User is offline

Thank you very much!

I will sleep better tonight knowing I am in the normal range.

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