EDIT: BEFORE you start out, see this is NOT an Explorer system and blow it off... stop. The procedures for recharging auto AC are the same (or 99% the same) for ANY system. What you leaern here is 100% applicable to recharging your Explorer's AC!

Recently I posted some info on converting to R-134 from R-12. Many posts since then have involved the aspects of how to properly charge a system. A recent project was the rebuild and recharge of a Sanden based VW bus system. (Sanden AC compressors, best of the best, even Learjet uses em). So in the interests of showing how it *ought* to be done here goes:

The setup... bus engine compartment and vacuuum pump and manifold - the system was rebuilt, and any old parts flushed, oil was added to spec, all we need at this point is to charge it with refrigerant -

http://www.explorerforum.com/data/503/15286dscn3624.jpg

The hookup at the compressor blue low/red high -

http://www.explorerforum.com/data/503/15286dscn3625.jpg


The vacuum pump -

http://www.explorerforum.com/data/503/15286dscn3626.jpg

After a few minutes of running -

http://www.explorerforum.com/data/503/15286dscn3622.jpg

On the electronic gauge at the same time -

http://www.explorerforum.com/data/503/15286dscn3668.jpg


Running about 20 minutes lowers it even more -

http://www.explorerforum.com/data/503/15286dscn3630.jpg

and about 45 mins even more - this is a good vacuum on mobile AC! No moisture or other non condensibles likely to be left in here! Note that we are not vacuuming the system (like a carpet) but evacuating it!!! This is not a process where we are "cleaning out" the system, but rather a process where we are removing all air and moisture -

http://www.explorerforum.com/data/503/15286dscn3632.jpg

Ok we are ready for refrigerant. Most important tool ? THESE !!! GOGGLES. PROTECT YOUR EYES !!!-

http://www.explorerforum.com/data/503/15286dscn3642.jpg

Ready to charge now. Hooking up the can to the charging hose, haven't punctured the can yet -

http://www.explorerforum.com/data/503/15286dscn3643.jpg

Another view, connected and ready -

http://www.explorerforum.com/data/503/15286dscn3644.jpg

With the can right side up and gaseous refrigerant ready, loosen this connection and bleed a little refrigerant through the charging hose to displace any air, then retighten it - do this for every new can you attach, you spent a lot of time getting rid of air, don't add it from your hoses !

http://www.explorerforum.com/data/503/15286dscn3645.jpg

We start by feeding liquid refrigerant into the "high" or red side, can is UPSIDE DOWN - And open the high side valve - (REMEMBER THE ENGINE IS NOT RUNNING AT THIS POINT - WE WILL NOT START THE ENGINE UNTIL LATER IN THIS PROCESS!!)


http://www.explorerforum.com/data/503/15286dscn3646.jpg

The pressures will slowly rise on the high side as the refrigerant is drawn into the evacuated system. The low side gauge will also start reflecting the pressures as they equalize within the system (high and low sides will equalize slowly in a non-running system, so you can see the pressure on either the high side OR the low side once they are equalized) -
Eventually, the first can will empty and a 2nd can, following the above purge procedure, will be started, until the system cannot take any more passively based on can pressurure. The temperature will dictate how much this is, but it's common to get into the 2nd can.... not to worry if it stops half way through, for when we cannot passively feed we can start the system and let it finish the job. Here, we have reached equilibrium pressures without any engine help - this is the low side gauge on the equalized system, easier to see more accurately the pressure on this gauge -

http://www.explorerforum.com/data/503/15286dscn3649.jpg

You can see above that the pressure is kinda like the temps on a nice day... good old R-12 closely approximates pressures for degrees F temps. In fact the red band that says R-12 is the temperature band for R-12. Ok, it's time for gas charging, so we close the high (red) side -

http://www.explorerforum.com/data/503/15286dscn3651.jpg

Now we are going to charge the rest as a gas. Through the low (blue) side. CAN UPRIGHT and once we get the engine running and the compressor and AC operating, in it goes -

http://www.explorerforum.com/data/503/15286dscn3652.jpg


As we start the engine. the high side will rise and low side will start to fall... he's the low side before we start adding gas with the engine operating the compressor-

http://www.explorerforum.com/data/503/15286dscn3655.jpg


We open the valve and start adding gas (can upright!)and the pressure jumps.

http://www.explorerforum.com/data/503/15286dscn3657.jpg


Why ? Because the system low side pressure is equalizing to can pressure, but taking it in at the same time, it will start to drop soon -
eventually the cooling can (yeah that sucker will get cold!) will again equalize pressures. You can speed things up by adding the can of refrigerant to hot water in a coffee can or similar, like this -

http://www.explorerforum.com/data/503/15286dscn3656.jpg

Once you do this the low side will jump again, but soon lower once the rest of the gas is drawn in. Here is the final charge on this system on the gauges -

http://www.explorerforum.com/data/503/15286dscn3659.jpg

Now to disconnect the gauge set. With the engine and AC running I disconnect the low side, and - this is important - add the cap, the schrader valves are a weak link in system leakage and caps really DO help!! - just make sure the rubber o-ring is inside and intact. Mineral oil it if you have some, that adds another barrier.

http://www.explorerforum.com/data/503/15286dscn3660.jpg

I leave the high side connected as I stop the engine -

http://www.explorerforum.com/data/503/15286dscn3661.jpg

The high side will SLOWLY bleed down from a HIGH pressure - time varies but wait til it is at a low pressure, this was after a few minutes, give it time - it can take a while to equalize, but be much easier to disconnect -

http://www.explorerforum.com/data/503/15286dscn3662.jpg

Last thing to do is to check for leaks. I use this sniffer to check for leaks, here at the compressor connections -


http://www.explorerforum.com/data/503/15286dscn3664.jpg

And at the main compressor seal, for the record I check underneath too, this was for photographic purposes... -

http://www.explorerforum.com/data/503/15286dscn3665.jpg

I'll also check wherever else it might be appropriate. So that done, the job is finished. In this case I knew exactly how much refrigerant to put in, if this was a top up I'd be watching low side pressures and monitoring vent temps more closely.

There is a big benefit of deep vacuum and taking a long time pulling a vacuum before you start; purging hoses to eliminate air and importantly wearing goggles. I kid you not, your eyesight is worth it, and I'm not being a woos. Please do it.

I hope this added something to our collective knowledge.

Happy, and cool, Exploring

Chris

Hope this added something to our collective knowledge.

It did to mine. Thank you!

Very nice post! Appreciate the pics.

Can you give us a rundown on what each piece of your equipment costs? The gauge set, vac. pump, "digital" vac. gauge/indicator (CPS gauge), and leak detector.

Also, I know you are careful about handling the refrigerant and keeping within the law. How do you know when the charging hose has been purged of the air? By smell, by sound, by time? I guess you can't avoid letting a tiny bit of refrigerant leak to the atmosphere during this important step.

What about putting an extra valve on the end of the line? This way you can evacuate the line with the rest of the system, and then close it to preserve the vacuum as you take the hose off the vac. pump and hook it up to the can? (Even just use the same valve that goes on top of the can?)

Lastly, you are highly regarded on this board as an a/c expert. Is refrigeration your job, or at least part of it? Or is it something you do on the side?

Thanks.

Robin... No I'm no longer doing AC for money, but I still do it on the side. I got interested in it years ago and still enjoy helping out others.

You are most correct about the hose end shut off. I debated posting that, (which technically you should have on EACH hose end) but wondered how many people would have those. The "perfect" way is just how you suggested, and once you are done you close all 3 valves, trapping refrigerant in the manifold and hoses. Then you hook it up to your recovery machine and recover the refrigerant from the hose/manifold set. Technically that is the law. I probably should have performed it in that way, but was afraid to scare off someone seeing me hooking up a recovery machine just to charge a system.

As for tools... just to give you an idea, and one certainly does not need this extensive a list -

I have a couple of vacuum pumps, I paid between $200 to $300 for them apiece. The gauge set is one of several, I think I probably paid $50 to $75 for it. The "sniffer" is something I picked up on E-bay for $50 or so. Same with the digital gauge, although I think I may have paid closer to $75 for it. I have an air powered flush gun (about $60 I think) and a refrigerant identifier (used E-bay for $200). I have a charging scale (for when you use jugs instead of cans, it reads in 1/4 oz, and I paid about $150 for it. Throw in a couple hundred bucks worth of compressor tools, temperature gauges and the like and that's about it, save the recovery machines..

I have a recovery machine (a Robinaire 25175 I paid about $275 for, and a recovery/recycle/reclaim machine - a Robinaire 17500B I paid about $400 for. It's main limitation is that it cannot recycle 134a from PAG oil systems - which is why I got it so cheap. I also have several tanks for recovery - 1 for R-12, 1 for R134 and one for R-22.

Overall I suppose I have around $1500 to $2,000 in AC specialty tools, but so far this year alone I have had to do 3 of my cars (2 total rebuilds) one for a friend, and 2 residential installations. The labor savings this year alone would have bought these tools. Over the years the tools have easily paid for themselves many times over.

Hope this answers your questions.

Happy Exploring

Chris

Several folks have written asking me how to find a reputable shop to do their AC - while they enjoyed the post, they don't want to do it themselves, which I respect.

So, that said how DOES one find a good AC shop? I can offer no real easy answers but can offer my observations. Doing mobile AC requires certification - it's not hard to get really, but not every shop always has someone around who is certified. Many dealerships for example contract out their AC work for just this reason.

My personal preference is to go to a shop that more or less specializes in Auto AC. Few can afford to ONLY do AC - they'd starve in winter, but see if it is a major aspect of what they do. How do they keep their shop? A neat clean shop says a lot to me. Ask ahead of time for an estimate - keeping in mind that with AC you often do not know the true extent of necessary work until you get into it. Ask about a warranty - how long will they stand behind their work? And, go with your gut instinct. If the workmen seem confident and know what they are doing, and you get a good "vibe" you probably will be a happy camper.

One thing people tend to forget is that it costs money to run a shop and pay wages. A shop rate of $50 to $75/hr is not unreasonable. There is little one can do to an AC system in much under and hour start to finish. Refrigerant will cost based on the type. R-12 is at least $25 a pound, R-134 should be closer to $5-8 a pound(or less). You might ask their charge for rerigerant and see if they are trying to charge you $20 a lb for 134 for example. I do not mind a mark up for handling refrigerant, but there is a limit. Ask if there is a fee should they need to recover your old refrigerant. Will they reuse it if they do or add new? (valid reasons may exist NOT to simply reuse the old, and they should charge you for it if they use new.)

I hope this is useful.

Cool exploring

Chris

If you found this interesting, you may want to peruse the post below. Although it talks about converting an R-12 system to R-134a, there is a lot of meat about AC in it generally too.

http://www.explorerforum.com/forums/showthread.php?s=&threadid=77331

Great thread just had to bump it .

Tis the season to bump this thread .

It was such a long post, I may have missed a few parts. I thought that I might add that when converting from R12 to HFC134, it is a pretty good idea to replace your accumulator or reciever drier while doing the conversion. Some R12 accumulators have a desicant bag that is not compatible with HFC134. Just a suggestion... great post!

Oh, and ester (polyolester) oil is a great substitute when doing a conversion as it is compatible with both PAG and mineral oil, but unlike PAG it isn't water soluble, so it helps make leaks more evident if the occur.

Eneurb thanks. I "think" I covered that, if maybe only in saying on a retrofit change the accumulator.... but as usual you offer sound advice... an older model may use dessicant suitable only for R-12. Recent models use dessicant useable for either. Replace the accumulator!

Also I use Ester based flush and use ester on my convesions. Thanks for pointing out the benefit.

Glacier, is this the adaptor I need to connect too the high side on my 92 explorer too my R12 gauge set ?

http://buy1.snapon.com/catalog/item.asp?P65=&tool=all&item_ID=11475&group_ID=1528&store=canada&dir=catalog

I cannot tell exactly from that description... but here is a link to a good place with inexpensive AC stuff... and directly to the adapter they sell

http://www.ackits.com/merchant2/merchant.mvc?Screen=PROD&Store_Code=AMA&Product_Code=90358

And finally a new forum home AC issues !

Is there a pic or diagram that shows the valve to recharge ac?

I am actually searching but have not found that info. Will continue to seach.

A short cut would be nice still.

Thanks.

Take a look at the above pictures. You could see the charging hoses connected to them with a manifold gauge set. I have a question. If an R12 system had the possibility of being converted to R134A from the previous owner, but has no updated R134A fittings (might have been removed after being recharged), would R134A do any damage if added to R12 just in case the system still had it?

I am using a single can of autozone stuff which comes with a snap on connector. The connector cant fit on the valve next to the radiator.

Take a look at the above pictures. You could see the charging hoses connected to them with a manifold gauge set. I have a question. If an R12 system had the possibility of being converted to R134A from the previous owner, but has no updated R134A fittings (might have been removed after being recharged), would R134A do any damage if added to R12 just in case the system still had it?

The R12 mineral oil does not dissolve well in R134.
http://www.epa.gov/Ozone/title6/609/technicians/retrguid.html

Thanks for posting that link! It has a lot of useful information. I guess if there is a doubt about what is in the system, it is better to evacuate everything, and start over with R134A. I remember before they had R134A that there was something being sold called "R12 substitute". It was supposed to be capable of being mixed with R12. It was only sold for a short time. Somebody that worked in an auto parts store told me that it was destroying A/C systems, and it was taken off of the market.

Shamaal is correct - the term for dissolvability of oil is called "miscability". R134 will not (for all practical purposes) carry mineral oil, because of the low miscability of mineral oil in 134. This is discussed in the Converting your R12 system to 134a thread in the stickies. Interestingly, mineral oil does form a barrier to the smaller 134 molecules so is a good bet for lubricating 134 system seals and even hoses prior to use. (I still prefer NYLOG as a O ring/seal lube though).

Q: When you evacuate the gas (R-134a) out of the system..........does it take the oil (PAG-100) out too?? So, do you have to replace the oil??

Aloha, Mark

The answer is "Depends". If your system had a real slow leak and eventually lost all your refrigerant charge, the odds are high you have virtually ALL the oil still in the system. On the other hand, if you blow a hose and has a near explosive loss of refrigerant the odds are you will have lost a significant portion of the oil along with the refrigerant.

When I run my recovery machine on a charged system, (My recovery machine separates oil), I often get 2 to 4 oz of oil out of the system, which I then add back in prior to recharge.

Thanks for the answer.........I had thought, that the evacuation/vacuum was taking, "everything out."

So, in the end, the shop using the right tools, will measure and replace the proper amount of oil. And, the refrigerant gets replaced based on the factory spec. X amount of oz. (also taking into account gauge readings and temps).

Whereas:

Shade tree guy w/ a slow leak shouldn't be overly concerned about oil loss.

And,

The shade tree guy doing an evacuation/vacuum w/o a proper recovery machine (that separates the oil and gas) will just have to wing it (as to replacement of oil). And, he will usually replace refrigerant based on gauge readings and temps (as he doesn't have an expensive scale).

Aloha, Mark

you pretty much hit the nail on the head there.

Where is the oil PAG 46 (I think) put into the system on a 96 Explorer?

NAPA says 7 oz go in.

I know I put some in the compressor....but where does the rest of it go?

Do I put any into the accumulator? If so, which pipe on it does it go in?

PDA1,

*Rule of thumb........(taken from the Haynes Book)



If no major oil loss has occured, and if only a single component must be replaced, oil can be added to the system by putting it into a specific component. Use the amounts shown below:

Condenser - 1 oz.
Receiver Drier - 1 oz.
Desiccant bag in VIR - 1 oz. plus the amount drained from the receiver-drier.
Evaporator - 3 oz.
Accumulator
a) Ford - 1 oz. plus the amount measured
b) General Motors
1) DA-6 - 3 oz. plus the amount measured
2) A-6, R-4, or V5 - 2 oz. plus the amount measured

It's important to note that, since oil distributes itself throughout the system during operation, it isn't absolutely necessary to add the oil to the compnent being replaced. With one notable exception, as long as the amount of oil lost during the replacement procedure is added somewhere, the sytem will be fine. The exception? If the compressor is being replaced, always put the oil into the compressorand not somewhere else.



Example:

I remove the old accumulator (my '94 Ford Explorer). Then, I drill a hole in the bottom of the accumulator and drain and measure the old oil.

Say that it's 2 oz. of old oil.

So, prior to installation of the new accumulator, through one of the pipes of the accumulator I'll add the new oil.........2 oz. plus an extra 1 oz. (3 oz. total).

*There are circumstances where a particular system type will spec. a different distribution for the oil, based on the "method of loss" (major, minor, quick or slow loss). And, if you didn't flush out the entire system (of the old oil)........sometimes, you may have to use your best judgment, about what amount of oil you believe is still retained in the "other major parts" of the system.

Aloha, Mark

PS.........BTW, the book will tell you the TOTAL amount of refrigerant and/or oil, for the entire system.

Do the math (too much or too little oil, is not good).

My 94 Ex has a stuck check ball on the fill side. It wont seal after I dump coolant into the system. It hisses like a pissed off cat. I tried to tap it with a nail punch, and it does make it slow, or speed up the leak, but wont stop. What do i do? I really need my a/c!

gmanpaint,

WELL.......the "old" R-12 systems used a schrader style valve core. Which were easily found and replaceable.

But, as you probably know, the "new" R-134a valves are different. I'd guess.......that the engineers of the R-134a systems would have thought about......"What if," for a similar leaking problem.

Check this out..........

http://qualitytoolsforless.com/Product.aspx?ProductID=3828

And, the Haynes book did mention, "Defective fitting replacement."

So then, you might have to replace the entire hose (or metal line) with the attached fitting/valve........check with a well stocked auto parts store.

Aloha, Mark

PS......individual valve cores and replacement ports can be had at FJC Inc. Download the catalog.....

http://www.fjcinc.com/

I have a 1994 Ford f250 I started out with a non-working unit. I replaced the compressor (new one not rebuilt) new condenser, new manifold hose, Removed evaporator, flushed and cleaned reinstalled, removed and flushed liquid line, replaced orifice tube, and accumulator….Filled with oil, 3 ounces at evaporator, 4 ounces at pump, 1 ounce at condenser, 1 ounce at accumulator…I then evacuated system with a vacuum for one hour at 30 (I don’t have a digital vacuum gauge like you have)…So then it was time to charge complete system…I have access to a 33 pound r134a tank so I connected that up to my gauges. I opened the red gauge and bled out the hose then tipped the 33 pound tank upside down and opened up the valve wide open and watched the red gauge pressure go up…the blue gauge went up also to about 70 psi…(it was about 70 degrees outside)…I closed the valve on the tank thinking now the pressure is stable and then decided to charge the rest through the low side. I then tipped the tank right side up and opened it wide open…I started the car and watched the gauges and noticed the blue gauge climbed rapidly.. I waited a minute or so and then observed it almost peg the neddle on my blue gauge….This made me uncomfortable so I shutdown the car engine and decided to bleed off the high pressue, So I disconnected the yellow hose from the tank and bled off the Freon….I then started the engine again and blue gauge was still pegged. I bled off more Freon and then the blue gauge went down about 50 psi…I then noticed the red gauge was around 100…I watched the compressor cycling off and on due to low froen now, the gauge reading didn’t move…Actually I googled my gauge readings high – low pressure, low high pressue and it said my compressure is going bad…I figured I ruined the compressor by running the pressure too high…Was I wrong to open the valve on my tank wide open for both the liguid and vapor charge? I used about 2 pounds of Freon during this process…I need some advice before I try this again with my new compressor….


PS - I also saw on other websites state you should never feed liquid refrigerant into the high -side...Only the low side...Could this also have caused my problem?
thanks Jim

gmanpaint,

WELL.......the "old" R-12 systems used a schrader style valve core. Which were easily found and replaceable.

But, as you probably know, the "new" R-134a valves are different. I'd guess.......that the engineers of the R-134a systems would have thought about......"What if," for a similar leaking problem.

Check this out..........

http://qualitytoolsforless.com/Product.aspx?ProductID=3828

And, the Haynes book did mention, "Defective fitting replacement."

So then, you might have to replace the entire hose (or metal line) with the attached fitting/valve........check with a well stocked auto parts store.

Aloha, Mark

PS......individual valve cores and replacement ports can be had at FJC Inc. Download the catalog.....

http://www.fjcinc.com/

I took off the cap and then the pc under it. the valve is diff then a schrader valve. It has a flat brass piston/washer looking pc with a spring around the end. It has a metal pc with sharp tabs on it that fits inside the fill cap thingy..lol, sorry. I tried to replace it with a normal valve, but no luck. In the process, I dropped the tab pc on the ground and lost it forever, sheesh. I am going to the parts store to see if they have a replacement, if not, off to the junkyard!




Ok, went to the local Pep Boys, and they had the stock replacement part for it for $7.oo. A/C will be back running by tomorrow! I will stop hijacking after this post. LOL!

The prohibition in feeding liquid through the high side is because you will blow up your can if the compressor is running. Yours wasn't. The high side IS a liquid side.... you didn't do anything that would have damaged your compressor if you ask me.

I'm wondering if you got the orifice valve in ok... I'm pondering this one.

I bought a kit to recharge my A/C (because it is not cooling enough). But the cap/clip from the bottle-hose doesn't fit in the port (I supposed this is the right port, next to the battery). I know I have to connect it to the low pressure port, but if it is not fitting is the right port?. The other one I can see is on top of a cilinder-can that I supposed is the compressor. I don't want even to touch that one.

Sorry for this simple question, but I read that it could be dangerous to choose the wrong port.
Thanks for your help.
:(

Thanks a million. Very helpful.

Finally, I got it!!! I was trying to charge the system in the wrong port (high pressure, next to the battery). That's why I couldn't connect the hose of the 134a can. We have to use the low pressure port.
I read one post here where somebody said something like this: " if you can not connect it that means it is not the right port..." The engineers thought about this when they designed the vehicle....
I looked for another one and I found one next the windshield washer tank. It was hiden... I connected the blue hose and perfect.... I charged my system, with no problems. Now my truck is cooling like a new car...