Any one know anything about A/C?

[sciroccos at earthlink.net (Jim Ruffi)]

Good info!

----- Original Message ----- 
From: "John Gates" <gatesj@mailblocks.com>
To: <timjmcconnell@gmail.com>; <haygood@myway.com>
Cc: <scirocco-l@scirocco.org>
Sent: Monday, June 20, 2005 9:48 AM
Subject: Re: Any one know anything about A/C?


> As I understand it what will cause the corrosion is moisture, not R134a 
> itself.  There is always moisture in the air, if the system has been 
> open to the air it needs to be positively sealed, optimally the 
> receiver/dryer needs to be replaced (so there is fresh dessicant that 
> can absorb any tiny bit of moisture in the system) and fully evacuated 
> for a decent period of time to make sure every tiny bit of air that 
> could contain moisture is out of the system.  At a high vacuum, around 
> or under 50 microns, water boils off nicely and comes out of the system 
> as a gas, but you need a real vacuum pump, cheapest I have found is 
> just under $200.
> 
> There is also something I remember about the mineral oil that worked 
> with R-12 being incompatible with the PAG oil that you would use in 
> R-134a.  All oil needs to be drained from the compressor and flushed 
> out of the rest of the system with a specifically designed flush to 
> really do it the right way.  Then the correct amount of PAG needs to be 
> added, the system sealed and properly evacuated and then charged with 
> R-134a.
> 
> It's either the PAG or the R-134a itself that combines with water to 
> form an extremely corrosive acid.  This is why any time you open a 
> system or it leaks on its own down to ambient pressure you have to 
> evacuate it.  Otherwise the system will work great for a few months or 
> maybe even a couple of years but eventually the acid will eat through 
> the condenser, evaporator, etc and you will have swiss cheese.  R-12 
> and the oil they used with it did not have this problem with moisture.
> 
> The conversion kits have been reported to work OK but I would bet that 
> there are varying degrees of success depending on the state of the R-12 
> system to begin with.  Obviously the results would be better with a 
> well functioning R-12 system that has not been opened or is otherwise 
> pristine inside.  And pros HATE to work on systems that were converted 
> with the magic kits.
> 
> I did a lot of reading on this last summer when I bought equipment.  
> Here is the best concise source of information:
> 
> http://www.ackits.com/index.cfm?fuseaction=flush
> http://www.autoacforum.com/categories.cfm?catid=20
> http://www.autoacforum.com/messageview.cfm?catid=20&threadid=9172
> http://www.autoacforum.com/messageview.cfm?catid=20&threadid=7931
> http://www.autoacforum.com/messageview.cfm?catid=20&threadid=7927
> http://www.autoacforum.com/messageview.cfm?catid=2&threadid=12769
> 
> The information I have gotten here seems to agree with everything else 
> I read on the Internet and the Haynes mobile A/C book I bought.  They 
> are trying to sell stuff by hosting this forum but the information is 
> good and there are a lot of people in there who know what they are 
> doing.
> 
> John Gates
> --
> '85 Scirocco
> '97 Jetta GLX
>