(GMC) Conversion of AC to 134A

[marcus mcgee]

My original Transmode is having a problem with thw AC Compressor and
it may need to be replaced. Has any one done the R12 to 134A conversion
and what was involved? Any suggestions?

Thanks
Marcus

 

[gilbert r. bethel]

I have seen it done but you will get less cooling with 134a. It was
recommended to me that I not use 134a on a vehicle that the air conditioner
is marginal at best (i.e. a large van with single unit). I would keep it
R12 if at all possible to ensure that the front ac kept the coach cool in
the hot summer time. I guess you could run the Onan and the roof units but
that would be hard on fuel economy.

If you decide to go with the 134a you will have to replace the expansion
valve/orifice tube, drier and all of the o-rings plus clean out as much of
the mineral based oil out to the system as possible. I would go to a
reputable automotive air conditioner specialty shop to have it done. I
would stay away from places like Pep Boys and the like as they do not
specialize in change over. It will be expensive either way you go. If you
think you can live with less efficiency from the unit then you may want to
consider the changeover, otherwise bite the bullet and pay the high price
for the R12. I don't know where you live but R12 is not very expensive in
Mexico. It is illegal to bring cans of it back into the USA. I don't know
about having a unit serviced in Mexico and then bringing the vehicle back to
the USA. One would have to check on that.
- -----Original Message-----
From: Marcus McGee
To: gmcmotorhome
Date: Sunday, April 05, 1998 12:28 PM
Subject: RE:GMC: (GMC) Conversion of AC to 134A

>My original Transmode is having a problem with thw AC Compressor and
>it may need to be replaced. Has any one done the R12 to 134A conversion
>and what was involved? Any suggestions?
>
>Thanks
>Marcus
>

 

[scott woodworth]

Marcus,

Don't do it. You'll be sorry in the long run. The R-134A
changeover is expensive and unnecessary. R-134A is only about 50% as
efficient because of it's higher required working pressures and
different boiling point. It also requires the following:

1) An oil change to PAG oil. The ester oil used in R12 systems is not
soluble in R-134A. PAG oil is corrosive, so the whole refrigeration
system will turn into junk in 7-10 years.

2) Replace all A/C hoses with teflon lined hoses. R-134A has a smaller
molecular size and will leak out faster than R-12 with regular hoses.

3) New receiver/dryer. Needs to be changed anyway with a new charge.
The desiccant inside will only hold a small amount of moisture.

4) Sometimes a new compressor is required if the original one is down on
compression. The R-134A requires almost double the working pressures as
R-12. If your compressor is weak, it will not be up to the task.

Here's some solutions:

http://www.frigc.com/ (This is one of the best I've seen.)
http://www.btt.org/EC-12a.html

The Frigc is 100% compatible with R-12 systems and even more
efficient. The EC-12 is a substitute made from organic gasses. They
are referred to as "drop-in" refrigerants. They allow you to keep your
system the way it is and save money while keeping it's original
performance.

Stay Cool...

- -Scott Woodworth

 

[gilbert r. bethel]

Thank you for the information. I am checking the websites out.
- -----Original Message-----
From: Scott Woodworth
To: gmcmotorhome
Date: Monday, April 06, 1998 4:13 PM
Subject: Re: GMC: (GMC) Conversion of AC to 134A

>Marcus,
>
> Don't do it. You'll be sorry in the long run. The R-134A
>changeover is expensive and unnecessary. R-134A is only about 50% as
>efficient because of it's higher required working pressures and
>different boiling point. It also requires the following:
>
>1) An oil change to PAG oil. The ester oil used in R12 systems is not
>soluble in R-134A. PAG oil is corrosive, so the whole refrigeration
>system will turn into junk in 7-10 years.
>
>2) Replace all A/C hoses with teflon lined hoses. R-134A has a smaller
>molecular size and will leak out faster than R-12 with regular hoses.
>
>3) New receiver/dryer. Needs to be changed anyway with a new charge.
>The desiccant inside will only hold a small amount of moisture.
>
>4) Sometimes a new compressor is required if the original one is down on
>compression. The R-134A requires almost double the working pressures as
>R-12. If your compressor is weak, it will not be up to the task.
>
> Here's some solutions:
>
>http://www.frigc.com/ (This is one of the best I've seen.)
>http://www.btt.org/EC-12a.html
>
> The Frigc is 100% compatible with R-12 systems and even more
>efficient. The EC-12 is a substitute made from organic gasses. They
>are referred to as "drop-in" refrigerants. They allow you to keep your
>system the way it is and save money while keeping it's original
>performance.
>
>Stay Cool...
>
>-Scott Woodworth
>

 

[rich and dottie major]

Scott,

Do you have any first hand experience with either one of the substitutes???
Do you know of anyone who has used either refrigerant??? Thanks

Rich Major
'78 Kingsley
Sugar Land, Tx

> Marcus,
>
> Don't do it. You'll be sorry in the long run. The R-134A
> changeover is expensive and unnecessary. R-134A is only about 50% as
> efficient because of it's higher required working pressures and
> different boiling point. It also requires the following:
>
> 1) An oil change to PAG oil. The ester oil used in R12 systems is not
> soluble in R-134A. PAG oil is corrosive, so the whole refrigeration
> system will turn into junk in 7-10 years.
>
> 2) Replace all A/C hoses with teflon lined hoses. R-134A has a smaller
> molecular size and will leak out faster than R-12 with regular hoses.
>
> 3) New receiver/dryer. Needs to be changed anyway with a new charge.
> The desiccant inside will only hold a small amount of moisture.
>
> 4) Sometimes a new compressor is required if the original one is down on
> compression. The R-134A requires almost double the working pressures as
> R-12. If your compressor is weak, it will not be up to the task.
>
> Here's some solutions:
>
> http://www.frigc.com/ (This is one of the best I've seen.)
> http://www.btt.org/EC-12a.html
>
> The Frigc is 100% compatible with R-12 systems and even more
> efficient. The EC-12 is a substitute made from organic gasses. They
> are referred to as "drop-in" refrigerants. They allow you to keep your
> system the way it is and save money while keeping it's original
> performance.
>
> Stay Cool...
>
> -Scott Woodworth