Since Freeze 12 is 80% 134A, the load will also increase on your condenser.
Here's what's involved in a full on conversion to 134A.
Retrofitting Air Conditioners to use R. 134a
Many owners of automobiles with R-12 refrigerant air conditioning systems
may be interested in a low cost retrofit/replacement of the original R-12
air conditioner refrigerant with EPA approved R-134a. The least cost
retrofit is simple and does not require major component changes. Basically,
the process calls for removal of the old refrigerant, installation of new
fittings, a new label and the addition of either a polyalkylene glycol {PAG}
or polyester {POE or ester) lubricant as well as the R-134a refrigerant.
O-rings, compressors and hoses do not need to be replaced if they are in
good shape. Obviously, if your system is flat, the leak(s) need to be
repaired.
Although the EPA does not have the technical expertise to recommend
procedures for each vehicle, the following recommendations are from one
service facility and parts wholesaler with extensive experience in
retrofitting vehicle air conditioners with R-134a. Arctic Air in Fort
Lauderdale, Florida, has been recognized as a pioneer in making this
retrofit/replacement.
This information is provided solely as a service to automotive technicians
who should rely on their experience and judgment in determining the most
appropriate steps in retrofitting any vehicle with HFC R-134a or similar
substitute.
1. Recover the R-12 according to SAE J1989 standards {this requires a closed
capture system generally available only at air conditioning service
facilities).
2. If the system is contaminated with water, oil, or other foreign material,
perform closed loop flushing.
3. Repair leaks and make any necessary parts replacements.
4. Add PAG or ester oil lubricant according to the exact specifications for
the system. Too much oil will affect system performance.
5. Replace the accumulator or dryer if this was not done during repairs. Use
an R-134a compatible desiccant such as XH-7.
6. Install the R-134a service ports. The Schrader valve cores may have to be
replaced depending on the design of the ports. Note that the service ports
for R-134a are reversed in size from those for R-12. The small port is on
the suction or low side and the large port is on the discharge.
7. Evacuate the system for 45 minutes at 29.5 inches of mercury. The
retrofit requires a long evacuation time to ensure complete removal of the
R- 12.
8. Charge the system with R-134a using a calibrated cylinder or weighing
scale. The retrofit generally requires the weight of R-134a to be between 75
and 90% of the original weight of the R- 12 (it is recommended that 75% be
installed and then the system be checked for excessive clutch-cycling).
Proceed in 5% increments until the clutch-cycling is
minimized. DO NOT EXCEED 90%.9. Check for leaks.
10. Complete the R-134a label and apply over the original R-12 label.
11. Test drive the coach with the AC running.
12. Do a performance check. High-side pressures should be within 10-15% of
the original R-12 pressures according to manufacturer's specifications.
Bob Palmer
rpalmer@ucsd.edu
robertpalmer@paulhastings.com
rpalmerbob@adelphia.net
-----Original Message-----
From: owner-tigers@autox.team.net [mailto:owner-tigers@autox.team.net]On
Behalf Of Steve Sage
Sent: Saturday, June 28, 2003 11:26 PM
To: rpalmer@ucsd.edu
Cc: Tiger Mailing List
Subject: Re: Off Topic A/C Question
Bob Palmer wrote:
>Steve,
>
>Freeze 12 is a mixture of 80% HFC-134A and 20% HCFC-142B that behaves, more
>or less, like HCFC-12 (R-12). I believe you will have to remove all of the
>CFC-12 if you use Freeze 12 or other similar blends................
>
Bob:
Thanks for the information. I've been doing a lot of reading on a couple
of the A/C discussion boards. A good number of do it yourselfers there
have used Freeze 12 for several years and are very happy with it. A
couple of them even said they just added a pound or so Freeze 12 to a
low R12 system in an old car, didn't do, or change out anything else,
and it's worked well for several years. That's possibly too good to be
really true. I haven't found any disaster stories about it yet, though.
I am going to get some kind of definitive information before I do
anything other than re-charge it with R12. I'm trying to find out how to
contact the actual manufacturer to get the info direct from the source.
I did find a shop today that says they'll sell R12 for $55 a pound, +
$45 for the test/service, etc. so, if it only needs a pound or so,
that's not a bad deal these days and I'll probably just go that route
for now. My real motivation for looking into the Freeze 12 is that
eventually R12 will be even a lot more expensive, plus, you can't buy it
retail, and I want to be able to work on my own A/C myself. Everything
I've read about 134a implies it won't work well in my system since it
requires a bigger condensor, and as we know, there's just so much room
to play with on a Tiger.
Steve Sage
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