[DML] R12 Availability (was Re: AC Service)

["aaron_t_graham" <aaron_t_graham@xxxxxxxxx>]

Here is how I understand it:  R-12 is a better refrigerant than R-134.
 That is, R-12 provides a more "powerful" endothermic reaction given
the same volumes and pressures of the respective gases.

A R-134 A/C system can be made to perform as well as an R-12 system. 
However, since both gases are condensed to a liquid form and then
allowed to expand, the R-134 gas must be compressed and expanded more
quickly.  This means that at several of the following must happen:

1) R-134 must use a compressor that compresses the gas more
effectively (because more gas must be compressed per unit of time),
thus drawing more power from the engine.
2) To help the condensation of the gas, a better condenser may be
required in some cases.  Same for the evaporator.  In most cases, the
same condenser and evaporator will work "well enough" for both
systems.
3) Depending on the configuration of the compressor/condenser setup,
it may be necessary to replace the lines and fittings between the
compressor and the condenser if the pressure in those lines is
increased significantly.  For instance, I would think a more powerful
compressor could be used to make up for a small condenser, but it may
be necessary to increase the pressure to facilitate more effective
condensation (assuming the condenser can handle the extra pressure).

I think most of the time people settle for a R-134 switchover where
the A/C is not as cold, but it's "good enough".  This minimizes
cost/hassle, and most of the parts don't need to be replaced.

Aaron
#1506


--- In dmcnews@xxxxxxxxxxxxxxx, "James Espey" <james@xxxx> wrote:
> Not sure about back east where Harold lives (and California where
everything
> seems to be deemed environmentally unsafe), but here in Texas, R12
prices
> have been stedily dropping back to early 1990 levels. The word that
I have
> received from our supplier is that as all the new cars are now
running R134,
> and so many people were frightened into, or otherwise convinced that
they
> needed to convert to R134, demand for R12 has dropped so much that
prices
> are now considered "normal" again. Of course, if you have a leak in
your
> system, it is against the law to refill it with R12. However, at
least here
> in Texas (and when I was in AZ) a properly functioning R12 system
in a
> DeLorean will outperform a DeLorean converted to run on R134.
> 
> James




To address comments privately to the moderating team, please address:
moderators@xxxxxxxxxxx

For more info on the list, tech articles, cars for sale see www.dmcnews.com

To search the archives or view files, log in at http://groups.yahoo.com/group/dmcnews 
Yahoo! Groups Links

<*> To visit your group on the web, go to:
     http://groups.yahoo.com/group/dmcnews/

<*> To unsubscribe from this group, send an email to:
     dmcnews-unsubscribe@xxxxxxxxxxxxxxx

<*> Your use of Yahoo! Groups is subject to:
     http://docs.yahoo.com/info/terms/