Automotive Air Conditioning Information Forum

bohica2xo wrote:Let's start with the flushing - What solvent are you flushing with? How are you removing it?

Next the oiling - it sounds like you had too much oil once, and are overcomplicating the oil charge.

The only way to be sure of the oil charge is to clean the system to bare metal & drain the new compressor. THEN add the 10 ounces - as much as the compressor will take, and the balance in the accumulator inlet.

Evacuation should be done with both service valves open. You can NOT evacuate only the low or high side of an assembled system - it is a loop. Once you have installed the oil charge & closed up the system, evacuate to a rough vacuum of 25 to 28 inches Hg, then close the valves & shut off the pump. Wait for the oil to de-gas for at least 15 minutes. Then evacuate to 29+ inches for 5 minutes. Close the valves & check for leaks. If the vacuum holds it can be charged.

You mentioned Harbor Fright. They sell an ok electric vacuum pump. The air powered unit does not create sufficient vacuum for refrigeration use and is a waste of money.

When it comes to charging, do NOT jumper the cycling switch. With the engine stopped, charge liquid through the high side. Hook up the first can as liquid & open the high side valve - it should take the whole can easily. CLOSE THE HIGH SIDE VALVE. Then start the engine & charge the remaining cans through the low side as always. The first can will be enough for the system to "short cycle" . This is ok, the cycles will get longer as you add refrigerant.

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This sounds like a good plan. Make sure you have quality gauges. You're spending a lot of time on this and should have the correct tools to complete the job once.

http://www.ackits.com/mt1416-santech-r1 ... oses-24615

Dougflas wrote:one thing stuck out of your plans. You were going to vacuum the system to see if it holds and then open it. Do not open a system while under a vacuum as it will draw moisture into the system. Instead, put some refrigerant or better yet, N2 if you have it then open the system.

Thanks Dougflas. That makes sense. I live near Seattle, lots of water in the air always.

Again, thank you bohica2xo and ACKits Tim. Every professional hint helps.

I am using quart cans of solvent based flush purchased from local auto store. One is by Interdynamics, one by TempSelect. Neither lists the chemicals, only states that the fluid is formulated to clean auto AC.

I take great care flushing. I always disassemble entire system and treat each component separately. I let the flush sit for a while to dissolve any contaminants. I remove the condenser so that it will drain by gravity. Then I repeatedly blow it with compressed air, let it sit in the sun for enough time to get warm and finish evaporation, then blow it again with dry air. Obviously, I am in not hurry. Sometimes it takes all day to do this job. But I can assemble this thing in an hour any more. My only irritation is a new accumulator every time, and defective compressors I receive and have to return - one wouldn't pump, one had frozen clutch.

One gentleman said I should only flush it with R134A. How much Freon would it take to do this? Each can of flush is about $15, so I possibly could do this as cheaply. And should I just do it to finish a flush with solvents? I can understand that if any solvents remain they would tend to reduce the efficiency of the expensive double end capped Pag oil I use and harm the compressor. I must reiterate that I have never had a compressor failure except for the very first one installed during R12 retrofit. I did not do this job, and it failed a year later, trashing the compressor. That is when I decided to do it myself. All components have been replaced since.

My first personal system failure was a loss of Freon. After a refill and loss again, I thought it was a small leak in the evaporator, so I replaced it. But now I am convinced it was the one hose that was never replaced with barrier hose during retrofit, which I just replaced. It was nearly impossible to even find this hose, so I had one built by an excellent firm , AutoACfittings.com in Jacksonville, FL. That is why I am taking great care this time to get it right.

I have never heard of the process of adding liquid refrigerant to the high side first. I have always jumpered the switch. Sounds like a good idea and will give it a try. Is there a specific reason for NEVER jumpering the switch?

I do have the Harbor Freight vacuum. I typically vacuum to max then let it sit for hours, even overnight to see if there are any leaks, and then do it again to assure that all the water vapor will have boiled out.

I sincerely appreciate your continuing response and assistance. I once purchased an online application on Auto AC and continue to gain expertise. Very involved craft.

RJ

The ID flush has a very low vapor pressure, and is essentially odorless - this makes it difficult to get all of it out, and hard to detect if it is still present...

Flushing with refrigerant works, but you need fittings & a recovery machine.

For things like a piccolo condenser, stronger solvents are fine - especially since you remove it from the vehicle. Find an old hose that mates with the springlock on the condenser inlet. Cut it off close to the fitting, and put a flare fitting on it to match the service fittings - 1/4 SAE to pipe adapters work well for this. Use a hose clamp.

Now grab your side can tap, and the yellow hose. Connect the yellow hose to the condenser fitting & the can tap. Insert a can of brake cleaner or carb cleaner in the side tap. Pierce the can as low as the tap allows, & hold it vertical for liquid. Let it go - blow the whole can through the condenser & follow it up with plenty of compressed air. When you can't smell solvent at the condenser inlet or outlet it is all gone. If the inside of the discharge port is oily, do it again.

Adding liquid gets as much refrigerant in to the system as possible before starting the compressor. Refrigerant returns oil to the compressor. Running the compressor with no flow in the system is bad. When the system is short cycling it is moving short bursts at decent volume. When you jumper the switch the compressor is just whanging away with no oil return. Jumpers sell compressors.

If you are trying to use the air powered Harbor Fright vacuum pump you will never get the moisture or non-condensable gasses out. I hope you have the electric one.

Again, THANKS Bohica2xo, great information. That is what I have been looking for. And yes, I do have the electric pump. It easily pulls about 30 inches of vacuum. System holding now for two days.

I am about to fire it up again. Will let you know what happens.

RJ

Hi Bohica2xo

I for got to ask. I do not have a side can tap, only the valved top can screw on device. Do you consider the side tap to be more effective? My brother in law mechanic once said that he thought this was a better device.

RJ

Side can tap is king of the hill. Never a fuss with an out of spec can thread.

AND it lets you access high volumes of other products like brake cleaner, keyboard duster etc. from aerosol cans...

http://www.ackits.com/85530-3-in-1-side ... side%20can

I have been using that unit for years.

Thanks bohicx2

Roger, will pick up a side tap. And, are you also recommending brake/carb cleaner for flushing, or just an after flush cleaner. I bought both today, and I guess I am pulling the condenser again. It is brand new, except for one flush before this last attempt to revive AC.

I am referring your site to my professional automotive shop owned by brother's in law. One is retired, and one is still working. Neither one of them have told me as much as you have about this mysterious craft.

Just for your info, I am a former USN whitehat and retired USMC Infantry Officer, four tours in Vietnam, computer programmer, 78 years old. Four cars, built my own solar heated two story log house by myself, did all the electrical, plumbing, concrete, carpentry and engineering. Know a lot of stuff, and AC is one of the most unforgiving challenges.

Thanks for everything
RJ

Wow. Thanks for your service.

A/C is not hard, just some rules that always apply. If you want "as new" performance you have to start with a system that is as clean as it was before the first charge went in. That way you can put in the exact same oil charge as the factory did.

I have not posted the story of how I learned the A/C stuff in a long time. I am actually a Machinist.

When I was a 17 yr old kid living on my own & still in high school in southern AZ, I wanted the A/C in my car to work. The local A/C "guru" had a shop that looked like it was half junkyard. Inside was a pig sty with filth & old parts everywhere. I pulled the A6 out of my car & drug it in there for a front seal. After telling me it would never work again unless I brought him the whole car to fix, he agreed to R&R the seal. I waited 2 weeks for this. It leaked just as bad after re-install... And cost me dearly. I told myself there was nothing he knew that I could not learn.

I realized that the local community college used the high school for a classroom at night. They offered an RSES course for "Refrigeration Service". I rearranged my night time work schedule to take the class. Slept about 3 hours on class nights. Half of that in an English class the next morning. Most of the guys in the class were over 30 & worked at a nearby power plant. They were amazed that I was doing this for myself.

After that my car was always cold. The HVAC in my home always works. The knowledge has saved me a lot over the past 45 years.

If you do pull the condenser & clean it, let us know what you find.

B.

Hi B,

I know your name, Tim told me. Good on ya for taking the initiative to get schooled when needed. I was an electronic technician in the Navy. Did you work in AC all your life?

But now, it may take some time to get back to RV AC. A few days ago my Reverse Cycle Chiller, an AC unit that pumps hot water into my house burned up another zone valve. I finally figured out that the actual rubber valve and stem was the culprit - partially froze up. Ordered parts from supplyhouse.com today - great site and service. I am tired of paying the installer of this system for continuous crashes. I keep notes on everything, study it all, and can fix this thing myself, but have a hard time finding the circuit board part - lost at least four of them so far, which they replace.

And now, on Nov 1, right on schedule, the sky goes black, wind begins to blow, snow in the mountains and maybe here. (wind knocks down miles of forest sometimes, sunk a floating bridge once, incessant rain last year, drought this summer). Seems always something to disrupt my projects. Garage is a mess, house needs attention. That is what happens to my winters. And can't get my RV in the garage, have to work under a metal carport cover, exposed to this stuff. Love it!

Thank you again. Value your experience and assistance very much. I will get it right this time and let you know how it works out.
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I expect to find most of the oil that was in the failed compressor now in the condenser, as the system only ran for a few minutes before the clutch failed and I shut down the engine. I never even got started with Freon. Before I returned the failed one, I tried again to drain oil, and little came out.

I installed 5 oz. in that compressor, but I could not get ANY oil to drain first to set a start point - never had an E6DH that would drain. 4-seasons states that there are 3 0z. installed, little tag on the intake port. There is no drain plug, just turn it over and hope it comes out the I/D ports. Yet, the one I took apart to use as a learning tool did contain nearly 3 oz., some in each end behind the reed valve plates. Because of the design of these plates, there is little chance of any drain through I/D ports just by spinning by hand.

As a test, I installed additional 3 oz. in the newest one before mounting it on the engine, then spun it by hand to see if anything came out. After assuring that the pistons are oiled and moving freely, I use a drill to spin it up slowly and continuously for a few minutes and it did disgorge about 2 oz. quickly. I take that as an indication that at least 3 oz. made it to the condenser before I got the engine shut off. Will flush condenser with brake fluid.

RJ