If anyone wants more info on retro fits for r12 to r134a go to
http//:members.tripod.com/~RockValley/air.html
It' not all that bad.
Mike Cabe
n Thu, 17 Jul 1997 09:41:45 -0700 "Richard Brown" <Richard.Brown@MCI.Com>
writes:
>Note: This was lifted from a previous message I received from Daniel
>Stern, so don't respond to ME if you have any questions. I'm no A/C
>expert... ;-)
>==========================================================================
>
>
>Basically, DO NOT(!) convert your R12 car to R134a or any of the
>R134a-based refrigerants (FRIGC comes to mind). They are far less
>efficient than R12 and R406A, GHG-X4, etc. Also, they are HIGHLY
>
>
>incompatible with R12-type oil. THey operate at radically different
>pressures, so calibration of R12 expansion valves won't be optimal.
>Also,
>since 134a is so inefficient, one must use larger compressors,
>condensors,
>and evaporators to get the same level of cooling as from an R12
>system.
>
>This is difficult and expensive to do on an existing system, so you
>get
>much less cooling with 134a. To convert to 134a PROPERLY so as not to
>shell any of the components, you're going to need:
>
>- Barrier-style hoses (The R12 hoses are
> permeable to the smaller R134a molecules)
>
>- All new seals and O-rings (ditto above)
>
>- A rebuild or thorough flush of your compressor.
> Which one you will need depends on the design of the
> compressor. Early CHrysler compressors, for instance,
> use an oil sump and pump which cannot be "flushed" of
> oil like non-sump type designs, and because 134a is so
> violently incompatible with 12-type oil, you have to get
> ALL of the old oil out.)
>
>- New receiver-dryer with XH7 or XH9 desiccant
>
>- And you should really purchase a parallel-flow condenser
> to try and make the system work at least marginally, if
> not optimally well.
>
>Now let's compare that to using R406a or GHG-X4:
>
>- They are MORE efficient than 12, yet it operates at
> similar pressures, so the expansion valve calibration
> will remain optimal and your existing condenser and
> evaporator will function MORE than adequately.
>
>- They are completely compatible with R12 type oil, so no
> system flush or expensive compressor rebuild.
>
>- You still need barrier hoses, because R12 type hoses are
> permeable to the smaller R406a factions' molecules.
>
>- Ditto new seals. (New hose-to-hose and component-to-component
> seals, you don't have to mess with any compressor or other
> internal seals).
>
>The choice is crystal clear here, isn't it?
>
>Now I have to ask YOU a question: Why are you converting to anything?
>R12 is still around, you know, and anyone who tells you otherwise is
>lying or ill-informed. There is plenty of it in the US. There is
>MORE
>than plenty of it in the US.
>
>Some garages will tell you that R134a is the only legal refrigerant.
>That's wrong. (You don't have to take my word for it, either. Go to
>the
>EPA SNAP (Significant New <refrigerant> Alternatives Plan) homepage
>and
>see for yourself that 406a and GHG-X4 have passed all the safety
>tests,
>are certified nonflammable/noncorrosive, etc.
>
>Some will tell you that 134a "moves more heat" than R12.
>That's also wrong. Some will tell you that no flush, rebuild, or
>anything
>else is needed when converting to 134a, and that you can just drop
>134a
>into an existing system. For most systems, That's dangerously wrong.
>Either use 12, or use 406a, or use GHG-X4.
>
>Information on conversions and refrigerant alternatives can be found
>at
>http://worldserver.com/ghg/index.html#GHG-X4
>
>
>Daniel Stern "a T3 2.2, a 2.5, and 2 225s."
>Licensed s.609 Automotive A/C Technician
>Automotive Headlamp Specialist At Large
> Website Items:
>http://ursula.uoregon.edu/~dastern <-----All Things Daniel and Pizza |
>
>
>
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