Flush Condenser ( anyone successful with this?)

[cthomasparr]

I see that flushing a/c components can be done, but is it practical? Has anyone ever cured a restriction in their condenser? i currently have a new comporessor in a system that is showing very high pressure on high side. I fully evactuated, no leaks, and filled properly. I suspect the condenser or expansion valve. Since I am probably going to do some kind of cleaning, I was thinking of trying to backflush the condenser. Anyone's experiences would be appreciated.

[tpollauf]

I'll jump in on this one as refrigeration is one of my specialties. Generally speaking, if a system is "pure" and no contaminants present, you should NEVER have any restrictions. Once you open up a system and repair it, change components, etc. you subject moisture and other possible contaminants to the system .... not good. Seeing how automotive systems are considered "semi-hermetic", as in the motor to run the compressor is external (cars engine) and not hermetic (internal motor). Anyways, did the new compressor come charged with the proper amount of in in it? Not sure on automotive compressors but hermetic ones all come pre-charged with oil. I've had rare cases on coolers/freezers not working properly due to excessive oil being trapped in the condenser. It's possible this could be the case for you. It certainly wouldn't hurt to "blow it out" and remove any old oil from the prior compresor and any that is trapped in the condenser. Dry nitrogen would be the preferred pressure gas to use BUT shop compressed air will also be fine. Just evacuate with a good vacuum pump when finished so you eventually remove all the moisture. As far as the expansion device goes, it's possible that you have a restriction there also. Most expansion devices have an internal screen (filter) to catch any debri, if any, from entering the metering device. Its possible that some crud, metal shavings, gasket material, etc. broke loose and traveled up to it which WILL create a high pressure condition. Poor airflow across the condenser will also create this condition.

What was the reason you had to change compressors in the first place? Hope some of this helps, even though I rarely work on automotive AC systems. I primarily work on Large Centrifugals, Absorbers, and commercial/industrial refrigeration systems. I still dabble with good old coolers and restaurant equipment also. In fact, one of my better customers just happens to be a micro-brewery! I take care of their ice machine, kegerator, walk in cooler, and roof top units. No invoice every submitted for my work. They just reward me with gift cards for free beer!

[zbyers]

They just reward me with gift cards for free beer!

Can't ask for a better method of payment!

[andrewclaus]

...No invoice every submitted for my work. They just reward me with gift cards for free beer!

I had to laugh at this too. I do home handyman and remodeling work for a friend who's a serious home brewer (eleven taps in the man cave right now). No money changes hands.

To the OP, sorry for the thread drift and good luck with your problem. Refrigeration is one of the few areas in which I have no proficiency.

[Bookworm]

I'm extremely inexperienced with A/C systems in cars as well. I can recharge, and MANY years ago I was involved with a complete flush and vacuum pump out, but I don't remember much about it. (1986-7)

I do know that last year, our A/C went south, and it was because of a build-up in the pipes - even as a sealed system, the lube and other crap can turn into a ball. The A/C guy (company my folks have worked with for decades) said he evacuated the system, then fired compressed nitrogen through it, and the blockage shot out. After that, putting the refrigerant back in had everything back and working good as new. Even with a 13 year old system, he said everything was good and nothing needed to be replaced. (My folks is now over 20 years old, and is still running well.)

[cthomasparr]

i decided to punt and order a new condenser and expansion valve. I found some opinions online that the condenser would not flush well as the passages are too small. Better to go with new and get the job done as far as I am concerned. Thanks for the help.

[cthomasparr]

I installed the new condenser which came with an attached receiver/dryer. I also bought an expansion valve.

First off, replacing the expansion valve appears to be a huge undertaking. After an hour of searching behind the glove box I would rather have scrapped the car than continue.

I did replace the condenser. replaced the gaskets and tightened up the connections. Ran a vacuum. It held while I went out for dinner. hours later I decided to charge the system. After the first 12 oz can I thought I heard a hiss and went around tightening all of my connections on the gauges. There was engine noise, fan noise, ... Somewhere into the second can an eruption from near the condenser attachment. loud hissing and mist rising up. I found that there was a loose connection between the receiver/dryer and condenser (the connection on the part they shipped and I didn't check).

It was still holding some pressure, but an unknown quantity was lost. I put in most of a third 12oz can and it seemed to blow reasonbly cool. Looking at the gauges alone, it appears to be undercharged. I based this on a generic chart for high and low pressure readings at different ambient temperatures with the compressor running. I still have plans to charge a little more until my readings agree with the table.

Anyone have experience and know if this is a reasonable way to charge? I was going to fill to the specified capacity and not overanalyze, but that opportunity is lost unless I start over.

[tpollauf]

Is your low pressure control "kicking out" the compressor intermittently? If so you're likely still a bit low. I believe 35 psi on the low side for R-134A would be close to normal suction pressure at around 2000 rpm. Been awhile since I've charged a car. Almost exclusively work on commercial/industrial AC systems.