R-12 Conversion to R-134a

I'm sticking with R-12 because I have a good supply of gas, but I've been doing some research on the Barrier Hose issue and the conversion process. As you may recall, the estimate to change over at Prevost was 40 - 50 hours in labor because of the hoses.

This is one paragraph about hoses from a very good Tech Article:

When R134a was first introduced, it was thought that all non-barrier/ nitril hoses would have to be replaced during a retrofit, but later testing has shown that the mineral oil used in an R-12 system forms a natural seal. In most cases, the R-12 hoses will perform well, provided they are in good condition. This is also true for O-rings, unless the fittings have been disturbed during the repair or retrofit, replacing O-rings should not be necessary.

The entire Article is here: http://www.shoptrac.com/r12retro.htm

I realize this is a "who gives a rat's ass" for later coach owners, but I would guess there is a bunch of R-12 guys out there and I question the mother ship (Prevost) on the need to spend north of $7,000.00 for a simple conversion.

Very good information Tom and I suspect there are a lot of owners without a big supply of R-12.

Our '91 Marathon was equipped with Prevost over the road air that was converted to R-134a. The hoses were never upgraded... the system worked great, we never had any leaks.

We were advised by a Prevost tech to consider upgrading the hoses when and if the system developed leaks.

Our 93 was upgraded to 134 and has the original hoses.

I've added 134 a couple of times a year to keep it cool and have not notice a big hole in the ozone over my head yet.

The new 134 replacement has a sealant and a dye in it and seems to last longer than the old "raw"134.

I estimate i spend less than $50.00 a year on freon. Seems practical.

Quote:

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Originally Posted by truk4u

I'm sticking with R-12 because I have a good supply of gas, but I've been doing some research on the Barrier Hose issue and the conversion process. As you may recall, the estimate to change over at Prevost was 40 - 50 hours in labor because of the hoses.

This is one paragraph about hoses from a very good Tech Article:

When R134a was first introduced, it was thought that all non-barrier/ nitril hoses would have to be replaced during a retrofit, but later testing has shown that the mineral oil used in an R-12 system forms a natural seal. In most cases, the R-12 hoses will perform well, provided they are in good condition. This is also true for O-rings, unless the fittings have been disturbed during the repair or retrofit, replacing O-rings should not be necessary.

The entire Article is here: http://www.shoptrac.com/r12retro.htm

I realize this is a "who gives a rat's ass" for later coach owners, but I would guess there is a bunch of R-12 guys out there and I question the mother ship (Prevost) on the need to spend north of $7,000.00 for a simple conversion.

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truk4u,

I am one of those that uses R-12 also, in both of my systems. Perhaps someday, R-134 could be in my future, but not until I use up the 30 pound cylinder I purchased.

Hector

The use of R12 is a good choice.

It runs at lower pressures and cools more efficiently than 134, and has less tendency to leak, all pluses.

But when you run out, 134 is a good substitute because even though your system may leak down a little faster, and you may lose some cooling efficiency it is tough to justify changing the system components and hoses when the cost to recharge is so cheap.

I did not say that in case the EPA is listening.

There is also a product called "Freeze 12" that is compatible with R-12 but does not have the enormous tax on it. It costs about the same as 134, but is chemically more similar to R12, but it's chemistry is just different enough to avoid the tax.

It can be mixed with R12.

Convenient!