[DeTomaso] A/C Question

[Art Stephens]

Chris,
     I vacuumed the system for more than an hour at 27-28",  I couldn't get to 29".  I put in 8.5 ounces of PAG oil from a can with some refrigerant.  I have a Sankyo rotary compressor.  I used a new dryer and a new expansion valve.  Most of the system has been sitting open for better than five years.  
Thank you,
Art

  ----- Original Message ----- 
  From: Chris Difani 
  To: Art Stephens 
  Sent: Sunday, September 03, 2006 7:26 PM
  Subject: Re: [DeTomaso] A/C Question


  Art:

  How long did you evacuate the system for? 45 minutes after the gauge hit "28" or so? Or an hour? It sounds (diagnosing over email is even worse than over a phone) that the system has air in it. Or some kind of contaminate. Did you put the right amount of oil in the compressor? 10 ounces or 12 ounces depending on the compressor. 

  But that sure sounds like a LOT of refrigerant for that system. Especially with that kind of gauge readings. 

  A lot of the AC guys do the evacuation for an hour, then they add the specified amount of refrigerant as per the factory spec's. Then add another half can or so, depending on what the thermometer is reading with the AC on, and fan on high. 134a is kind of notorious for not creating as much "cold" as 12 does in a system that was originally designed for 12. But if you've replaced the original York compressor with one of the rotary varieties, then you should be close to a 12 system, in terms of output "cool" and air flow. 

  But in any case, the key is the system evacuation, the replacement of the dryer (if it's been exposed to open atmosphere, or been in use for a few years), and then the installation of the factory recommended amount of refrigerant.

  Not that I'm an expert, but that's what I've found in my studies, and the few systems that I've successfully recharged. The evacuation is ususally best done with one of the Robinair vacuum pumps that they make for the AC trade. The converted refrigerator compressors can work... but I've never seen them get the system "down" as far as a good commercial pump will.

  Chris

  Chris Difani
  '73 L #5829 "LITNNG"
  Sacramento, CA
  Email: cdifani at pacbell dot net
  Chris





  ----- Original Message ----- 
  From: "Art Stephens" <artstephens at charter.net>
  To: <detomaso at realbig.com>
  Sent: Sunday, September 03, 2006 6:05 PM
  Subject: [DeTomaso] A/C Question


  >     I have already added 75 ounces of 134 refrigerant to my newly converted system.  The gauges don't climb above 20 psi on the low side and 210 psi on the high side,  in 90 degree weather.  What gives?  My instructions say I should see higher numbers.  Do I just keep adding more?  At ten bucks a can,  I figured I better start asking some questions.  The air blows cold,  but I could stand colder.
  > Art
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