RE: [DML] conversion to 134a

["Tom Tait" <TTait@xxxxxxxxxx>]

Fred:

 

First of all, while R12 is expensive, it is not impossible to get or
illegal.  Most but not all here will agree that it cools a bit better
than 134a.

 

I'm guessing that you havn't done a lot of A/C work, no offense
intended.  If its all old hat to you, you can buy adaptors at pep boys,
but that's a very small part of the equation for most of us.

 

If you are considering changing to 134a I presume its because the R12
system isn't working properly, and probably needs repair, or at least a
recharge.  

 

Properly converting to 134a will require more than just the connections.
First of all be aware that there are three main hoses in the A/C system,
and they were designed for R12.  Note that even when new these hoses
were not designed to hold 134a, and that the individual molecules can
and will slowly leak out of the system through the hoses themselves.
Its not a fast process, but it happens.  The O rings in the stock system
aren't for 134a either, but they can be replace with 134a compatible
ones.  If not they will leak.  Note that you can get modern hoses from
Specialtyauto.com that will go in fairly easily and are compatible with
134a.  They aren't cheap, but the pricing is fair if you need new hoses.

 

You will need to properly evacuate the remaining R12 (using a recovery
system, etc, something an AC shop can do).  You would then likely want
to replace the oil in the system too.  At this point the system is
empty.  .

 

This is really the right time to replace your accumulator/dryer too.
Almost like an oil filter, one of its jobs is to keep moisture out of
the system which prevents corrosio0n and damage.  If your system has
alsway either been under pressure or holding good vacuum after an
evacuation, its not going to have much moisture in it, but if the system
has lost pressure, you have moisture in there.  You will usually find
that the warranty for almost any piece of new AC hardware requires that
a fresh accumulator be installed.  That should serve as an indication of
how important this part is.

 

So you replace any defective parts, you replace your o rings, put in a
new accumulator, 134a compatible oil,  and then the system gets vacuumed
down using a commercial AC vacuume pump and gauge.  It needs to hold
that vacuume without leaking for at least an hour or two, even better to
let it sit overnight.  Then you know your system is sealed.  If it holds
vacuume pressure, you hope that it also holds positive pressure.  THEN
you install your 13a fitting from Pep Boys and charge the system.  

 

You can buy "complete kits" to convert to 134a at most auto parts
stores.  They will contain a special oil, some adaptors, some stop leak,
and some coolant.  Knowing now what a professional shop would do, or
what y9ou should do to do it legally and have it work well, you can
guess how well those kits will serve you in the long run.  You wouldn't
expect a can of fix-a-flat to actually repair your tire, those kits are
kinda an equivalent (IMHO).  I'm sure others have used them and will
report good results,  Thats why we have a forum. 

 

In brief, if you just need to add a little R12 and you don't have a
major leak, do that.  It may be your cheapest good option, and it will
run cooler on R12 for sure unless you go through real heroics.

 

If it needs more than a partial recharge of R12,  either fix it and keep
the R12 for the added cooling capacity, or embrace the much cheaper 134a
and its slight limitations, but do the job right the first time.

 

One other option is Freeze12, an R12 substitute priced about the same as
134a and readily available.  It's a blend of 134a and other gasses that
is compatible with an R12 system.  You could blend it with R12, meaning
simply add it to the system with no evacuation, but that's technically
illegal to blend them.

 

Finally, for those really serious about dong their own AC work there are
inexpensive online courses that will get you IMACA certification, so you
can legally buy and use R12 and any other refrigerant you like.  It took
me less than an hour  and $20 or so...

 

Tom

#10902

 

PS - for those of you who do use 134a - Big Lots (formerly Pic-and-save)
has new cans for a couple of bucks each - it's a chemical gas, any brand
should be as good as the next.

________________________________

From: dmcnews@xxxxxxxxxxxxxxx [mailto:dmcnews@xxxxxxxxxxxxxxx] On Behalf
Of Fred Phaup
Sent: Thursday, June 21, 2007 7:26 PM
To: dmcnews@xxxxxxxxxxxxxxx
Subject: [DML] conversion to 134a

 

Hi

I'm new to the list and need help on how to convert the AC to 134 A from
the r12.

I have looked around and have not been able to find any connections.
High or low sides.

Any help would be appreciated.

Thanks, Fred

1981 #1765

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