AC re-charging problem


avid

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I was following this guide "Resurrecting Your Ford Ranger Air Conditioning" from the forum here, and I'm pretty sure I bungled it up. I replaced all the AC parts, pulled a vacuum and was ready to re-charge the system. So I was in Appendix C: Charging the System. #11 says "With the truck off, open both the blue and red valves on the hoses next to the trucks refrigerant lines" and #12 says "Open both valves on the manifold portion. This will allow refrigerant to equalize on both sides of the compressor." So I did this, and wasn't exactly sure what "equalize on both sides of the compressor" means. It kept drawing in refrigerant and I kept expecting it to stop when equalized. I ended up putting in the full 30oz. (spec for my 1998) without ever moving onto the next steps where you close the high side, start the truck, etc.,. So basically, I put the 30oz. into both high and low ports without the truck running. When I started the truck after and turned on the AC to full blast the air never got cold and the compressor clutch never engaged. I'm still not sure what it means to open the manifold valves to "allow refrigerant to equalize on both sides of the compressor" but I now suspect this should have just been a brief opening. Don't know.

So my question is this: How bad of a screw-up was this and what should I do now?
 
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Denisefwd93

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Edit: I should not try to help without using my desktop I'm too old and feeble late at night to be doing so on a cell phone! 😵

The manifold valves are for allowing refrigerant to and from the system, If both sides are open refrigerant will Short circuit from one side to the other side manifold like a big u. good when you're evacuating but not for reading pressures,
BTW, you should only charge into the high side when adding refrigerant to the system (not running) after evacuation (Red hose) before start up. (Can upside down for liquid)
you will see the low side gauge slowly come up, (equalization )

Yellow hose is common to both valves on the manifold but you never charge both sides at the same time. You don't want liquid refrigerant coming to the compressor you want to going away from the compressor, when it is started.

rather than trying to figure out what you did wrong or right let's start from scratch,. Pictures from you would help a lot.

A fully charged system when it is not running, will have a static pressure equal to the pressure in the refrigerant can at the same temperature out doors. (Ambient temperature)

Do you know how to read a temperature pressure chart?

When you start the system if there is not enough refrigerant or both valves on the manifold are open you would not get enough operating pressure for the compressor control (low pressure switch)

With just a blue (low side) hose connected to the service valve on the receiver evaporator and the manifold gauge closed, start the engine and see if it kicks in,. if it doesn't, jumper the switch see if the compressor starts running with the engine check the low pressure don't run too long, just enough to get a reading you will get a reading from the manifold gauge, with gauge valve closed,
Low side charging is done with vapor (can up) this is called topping off adjusting the charge. you can take a while to charge a whole system through the low side because the refrigerant can will keep getting cold as the vapor comes off the top.


In order to get help you always need to know outdoor temperature, and low side pressure people can get in trouble or confused with the high side pressure, so I usually don't bother with it too much. There is a safety release in the unlikely event it's grossly overcharged.
 
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adsm08

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BTW, you should only charge into the high side. (Red hose) so yellow hose is common to both valves on the manifold but you never charge both sides at the same time.
This sounds wrong to me, for more than one reason.

All the AC service kits like AC Pro (No, I don't like them nor do I condone their use) all charge from the low side, so you can use the compressor to draw the refrigerant in.

When I do a vacuum charge without a pump I usually only get about 1/3 to 1/2 of the system capacity in before I run out of vacuum. Charging on the low side helps to pull the charge in, where charging on the high side can get system pressure over bottle pressure. Low side charge also means the refrigerant is going in before the compressor, so you don't run it dry if you have to use the compressor to pull the charge in while the system is low.
 

Denisefwd93

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It is wrong! when I was editing somehow I lost where I said, you charge on the high side when the system is not running (dumping liquid in). my bad I will correct that!
 

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It didn't sound right to me either... glad it is getting fixed.

When the A/C system is static (compressor not ON) you can charge with liquid or gas on either side or both. When the system is dynamic... only charge on the low side... and only with gas. Liquid refrigerant could be pulled into the compressor and ruin the day.

To the OP... you didn't do anything wrong that I can see. Sounds like you just need to take a breath and do a little diagnosis. Start by looking at the link that Denise provided and read the gauges. I agree with adsm... typically you have to get the system dynamic to fill it. Are you sure the refrigerant isn't leaking out as fast as you put it in?
 

Denisefwd93

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Hey we all make mistakes, especially when I'm trying to write anything more than a line or two on a cell phone!
 

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Thanks for the replies, guys.

rather than trying to figure out what you did wrong or right let's start from scratch,. Pictures from you would help a lot.
Thanks for your response. I didn't take any pictures of the guages, or anything else for that matter, while I was filling. The issue really is the procedure I used to fill, which I tried to explain as well as I could. I can't recall what the gauges were doing exactly when I was filling because I wasn't expecting to need to read them at that point. I thought this "equalizing on both sides of the compressor" step would be quick and obvious. When nothing happened indicated that step was complete, then I was in no-man's land.

\Do you know how to read a temperature pressure chart?
I think so, but I mean if you have to ask... ?

When the A/C system is static (compressor not ON) you can charge with liquid or gas on either side or both. When the system is dynamic... only charge on the low side... and only with gas. Liquid refrigerant could be pulled into the compressor and ruin the day.
Interesting.

To the OP... you didn't do anything wrong that I can see. Sounds like you just need to take a breath and do a little diagnosis. Start by looking at the link that Denise provided and read the gauges. I agree with adsm... typically you have to get the system dynamic to fill it. Are you sure the refrigerant isn't leaking out as fast as you put it in?
Well, I checked the pressure this morning and everything is at zero. There was a noise in the condensor when I was filling that was sorta like a hissing but sounded more internal and I thought it was just how it sounded when filling. I didn't see or feel any venting by it, but I don't know. I feel so stupid. Before adding coolant the system was holding a vacuum.

So if there's no pressure in the system now, should I see if I can pull a vacuum again?


Note: This whole process has been complicated by the fact that Autozone's loaner vacuum pump and manifold gauge set are missing parts and include incorrect instructions, etc.,.
 

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For $100 you can buy a vacuum pump and set of gauges on ebay. I doubt that you were holding a vacuum. Suck it down and hold it for an hour or so before you worry about R134a. If it holds for an hour...with the pump off and the gauges closed, maybe there are no leaks.
 

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When the A/C system is static (compressor not ON) you can charge with liquid or gas on either side or both. When the system is dynamic... only charge on the low side... and only with gas. Liquid refrigerant could be pulled into the compressor and ruin the day.
This part is also important. Getting liquid into the suction side of the compressor, or "slugging" can lead to hydro locking.

Keeping the port of the can you are filling from up will pretty much eliminate the possibility of brining liquid in, but having the can below the level of the manifold also helps reduce the changes of sucking in liquid, as the stuff tends to evaporate on the way up the hose.


To the OP... you didn't do anything wrong that I can see. Sounds like you just need to take a breath and do a little diagnosis. Start by looking at the link that Denise provided and read the gauges. I agree with adsm... typically you have to get the system dynamic to fill it. Are you sure the refrigerant isn't leaking out as fast as you put it in?
I agree, if you got 30 oz in and it stayed there you did everything right, and have another, probably electrical, issue.
 

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For $100 you can buy a vacuum pump and set of gauges on ebay.
Yeah, probably old Autozone loaners or equivalent. I'm not interested in owning those two items as I hope this is the last AC job I ever do.

I doubt that you were holding a vacuum.
Interesting. Why do you doubt this?

Suck it down and hold it for an hour or so before you worry about R134a. If it holds for an hour...with the pump off and the gauges closed, maybe there are no leaks.
I had the vacuum running for several hours over two days, as suggested in the tutorial I referenced in the original post.
 

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This part is also important. Getting liquid into the suction side of the compressor, or "slugging" can lead to hydro locking.

Keeping the port of the can you are filling from up will pretty much eliminate the possibility of brining liquid in, but having the can below the level of the manifold also helps reduce the changes of sucking in liquid, as the stuff tends to evaporate on the way up the hose.
Thanks for replying. I was shaking the can at about waist level with the gauge set suspended from my hood, which was raised and supported. So anything from the can would have had to travel up to the gauge set and then down the high and low hoses.

I agree, if you got 30 oz in and it stayed there you did everything right, and have another, probably electrical, issue.
I did wonder if maybe the new compressor was faulty. There were no problems previously with the AC system: it just leaked all the coolant out over several months and then sat opened up/disassembled for a year and a half while I replaced the engine.

Did you see where I checked the pressure this morning and now it's showing zero pressure? I was wondering if I should hook the vacuum back up to it and see if I can get it to hold the vacuum again- what do you think?
 

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Update: Definitely not holding a vacuum now. I can't even get it below -10Hg while running the vacuum where previously it would go to -27/-28Hg almost immediately. So maybe one of the new components I installed was faulty to begin with, or something in the way I charged the system caused a leak. Right now, I'm suspecting it is the condensor due to the noise I heard there while I was filling.

I'm unfamiliar with how dye works. Is it an additive in a can of r134a? Will dye work with no vacuum in the system? I guess I suppose so as that would be the only time one would really need it. I guess that's the next step.

Edit: Also, since I'm having to open up the system again will I need to replace the accumulator/drier?
 
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Denisefwd93

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I would suggest you do not use air pressure, in the trade we use nitrogen,. You already lost couple pounds of refrigerant,. you probably don't have nitrogen you probably have an air compressor and you probably still have a bottle of refrigerant, it is against the law to use refrigerant pressure testing and leak testing because you're purposely venting it to the atmosphere but we all know what everybody does, the single best leak detector is liquid DAWN, with a little bit of water mixed in,

Don't know if your 98 hoses are the same as the older rangers, where the high side connector is a poppet not a Schrader valve they l always seem to. leak. Connections are the first thing to scrutinize look for traces of oil on the condenser which is hard to do because where you need to look is on the back side between it and the radiator. The evaporator is near impossible to access without taking the whole works apart, you can borrow buy or use a sniffer or look for oil traces.

It's not easy, good luck!
 

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I would suggest you do not use air pressure, in the trade we use nitrogen,. You already lost couple pounds of refrigerant,. you probably don't have nitrogen you probably have an air compressor and you probably still have a bottle of refrigerant, it is against the law to use refrigerant pressure testing and leak testing because you're purposely venting it to the atmosphere but we all know what everybody does, the single best leak detector is liquid DAWN, with a little bit of water mixed in,

Don't know if your 98 hoses are the same as the older rangers, where the high side connector is a poppet not a Schrader valve they l always seem to. leak. Connections are the first thing to scrutinize look for traces of oil on the condenser which is hard to do because where you need to look is on the back side between it and the radiator. The evaporator is near impossible to access without taking the whole works apart, you can borrow buy or use a sniffer or look for oil traces.

It's not easy, good luck!
Thanks. I replaced all parts, including hoses, so the high and low valves are new. The only parts re-used are the sensors. I did hear some hissing at the condensor, possibly it's connection to the low pressure hose, while charging. Thought it was just the sound charging makes but now realize it was probably leaking that I was hearing.

Can you think of a reason why the system would hold a vacuum originally but then leak once refrigerant was added?
 

avid

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Are you sure the refrigerant isn't leaking out as fast as you put it in?
I am now thinking this is what happened. Is there something in the process of adding refrigerant that could cause a leak in a system that was previously holding a vacuum?
 


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