Re: AC pressure switch field replaceable?



Kevin wrote:

<HLS@xxxxxxxxxx> wrote in message
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"C. E. White" <cewhite3@xxxxxxxxxxxxxxxxxxxx> wrote in message
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"Don" <don@xxxxxxxxxxxxxxxxxxxxxxxxx> wrote in message
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EACTLY! And the conversion will NEVER cool as well as R12 in a
system designed for R12. Also, however much a system leaks R12, it
will leak HC134 considerably worse.

I have to disagree. when I sold the truck.

Ed

Actually, Ed, I have not had my older unit converted yet, but intend to do
so.

The local shops here say that the 134a conversions, when properly done,

are

very successful and cool just as well as the Freon systems.

I respect Don's expertise and good advice on this board, and will comment
from a personal perspective when my conversion is complete. (The shop
here is locating the leaks in the old system right now - most likely the

GM

compressor shaft seal - and then we will proceed.)




Condenser size and air flow is the main issue on r134a retro fits. R134a has
a higher operating pressure and the condenser runs much hotter than on R12.
In larger vehicles like pick up trucks and large cars the R12 condenser is
usually large enough and the airflow is sufficient to handle the conversion
well. On small cars with tiny condensers and electric fans there is often
not enough condenser cooling to remove the excessive heat and the system
performs accordingly. The issue of oil is also less of a problem on systems
that have a larger capacity. You can leave some of the old mineral oil in
the system and it just separates from the refrigerant and settles down in
the condenser and accumulator. The adder PAG oil is picked up by the r134a
and lubricates the compressor well enough.

I thought that on retrofits where there was NOT a complete system flush and dryer replacement that Ester oil was recommended?

Bob




On a small system, if any old oil
is left it displaces enough total volume that the system is less efficient
due to the lower volume of refrigerant that will fit in the system..
Non-barrier hoses on older systems are not usually a problem because the
mineral oil has permeated the pores in the hose and keeps the smaller r134a
molecules from seeping through. Bottom line, r134a retro fits can and do
work, but depending on the make and model, you may have to make some
modifications for it to work well.

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Relevant Pages

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