View Full Version : R12

15-12-2002, 12:47 PM
I was working on a old car the other day it had the remains of R12 in it. Working on containers with R12 in them I usally retrofit them to R409a can this be used as a drop in for car air conditioning system. The ambient is low temp but would it cause problems when needed in the summer if we ever get one in the uk cheers

15-12-2002, 09:36 PM

I always used to use R413a as a retrofit for R12 car systems.

It is compatible with mineral oil and the nitrile seals used; the pressure were similar to R12 and the efficencu was pretty good.

Beware of used some of the new mixes as the higher condensing pressures could blow the condenser or hoses.

Good luck with it anyway.

Karl Hofmann
02-01-2003, 12:35 AM
Well , this is an interesting site!. Hope you guys dont mind me butting in.

The vast majority of my work is automotive, though I have started to install smaller split systems over the past 12 months.

Regarding R413a I have used it for the last 18 months and it does work pretty well, in fact performancewise I cant tell the difference between R12 and R413a and best of all the systems cant tell the difference either, the compressor on the first vehicle that I charged is still running sweetly.

02-01-2003, 12:15 PM
409a will have higher pressures that R12, I would usev with caution! 401a is what I use a drop-in, pressures are higher but not by much, also the effeciency is higher and the charge lower.
Regards. Andy.

03-01-2003, 07:31 PM
Originally posted by Karl Hofmann
Well , this is an interesting site!. Hope you guys dont mind me butting in.
Hey, welcome Karl...........you butt in whenever you want. All input is useful (well normally:D ) and a fresh viewpoint never hurt anyone.

Karl Hofmann
04-01-2003, 10:13 PM
Thanks Brian, I'm not too sure if my view is fresh or just plain wierd! I have come in from outside the industry (designing and building refrigerated truck bodies in Dubai) and like to think that I have a fresh perspective to things. At the moment 99% of my work is automotive but the car manufacturers do their best to prevent guys like me from working on their electrical systems, VAG and Mercedes even have some compressors that must be "coded" to the engine management system before they will operate. Over the last year or so I've decided to move towards installing split systems into smaller shops, offices and homes. There is a ton of stuff that I dont yet know so I guess that I'll be asking more questions than I can answer.

Peter Croxall
07-01-2003, 09:17 AM
Hi Karl,
It's great to hear from any new postee. I've been toying

with changing the gas on my old Jag, (as I tried to run the A/C on

the 2 hot days we had last year, no luck. Very low back pressure)

So I guess the old R12 will have to go :)

Have I misunderstood ???, do you mean R413a or R134a. ( was it

a typo ??)

If you mean R413a...where can I obtain it and also any

information on it. I was contemplating using RS24 ( supplied in

this country by Refrigerant Products Ltd ). It is a blend, but is

supposed to be very close to R12, but with a better performance.

Have you heard anything about this product?

Karl Hofmann
08-01-2003, 07:26 PM
Hi Peter,

It's not the summer heat (Ha!) that gets to me but the humidity, I'm sure that it gets worse every year.

R413a isn't a typo, its a blend more commonly known as Isceon 49 and is sold through all the wholesalers, I get mine from RPW, some guys incorrectly call it R49. It does work well on later R12 systems as the manufacturers had already changed their systems to accept R134a so they already have compressor shaft seals, O Rings and flexible hose that will work with R134a.
R413a is mainly made up of R134a with a couple of other refrigerants thrown (Technical aren't I?) in to carry the mineral oil (R134a and mineral oil just wont play ball together)

I always change the reciever/drier to ensure that the dessicant inside is compatable with R134a. On earlier cars there is an issue of compatabillity between R134a and the seals and the flexi hoses which should be barrier hose with bubble crimped ends (Rather than the barbed fittings used with R12) otherwise the system could leak quite quickly (Although there some who recon that the mineral oil in the system soakes in to the material of the hose and forms its own barrier).

My preferred method of doing the job is to break down the system completely, drain the compressor of oil, throw the old drier and TXV, make up new hoses with barrier hose flush all components (Except compressor) with Brake parts cleaner and reassemble using new "o" rings compatible with R134a and the appropriate amount of 100 viscosity PAO (not PAG) lubricant. Vacuum down well and charge with R134a by shorting the cooling fans so that they run constantly and charge as a vapour untill the high side is about 2.5 times the standing pressure. Return the fans to normal fit a couple of the unique R134a charging ports and stick a label under the bonnet stating Lube, refrigerant type and weight.

Oddly enough only people who really love their cars bother with a full retrofit, the guy with the 250 Ford Granada walks away so I offer him the much cheaper option of the R413a and no guarantee! Many older cars never pass the pressure test.

I have heard of RS24 but dont know much about it many of the R12 drop ins are R22 based and offer their own problems, R413a works for me.

As you can tell Peter, older cars can be an absolute pain in the backside, although the newer cars dont seem to last much longer than two or three years, the manufacturers do love to clamp alloy pipes with steel clips. It is almost like they're designed to leak!!!! and yet we must be so carefull about venting refrigerant! :mad:

08-01-2003, 07:41 PM
Hi, Peter:)
if Iceon 49 is anything like Isceon 69L it will have a hydrocarbon component such as butane/propane, that will be the remainder of the mix.
As stated the pressures will compare, not as common as say R401a (or probably as cheap).
Isceon 49 59 and 69 were all developed with help and trials by Star Refrigeration and (Marc says Star is not a technically inovative company):p

Regards. Andy.

08-01-2003, 11:04 PM
Hi Karl. Charge R134a as a vapor?

Karl Hofmann
09-01-2003, 08:21 AM
Yup!! As a vapour through the suction port (engine running A/C switch to on or if the car is fitted with climate control, econ mode must be disabled). Once the low pressure or trinary switch reads 30psi the electromagnetic clutchshould engage, enabling the rest of the charge to be drawn in. This is not a problem with R134a, but sinceR413a is a blend I feed my manifold with liquid and then throttle the refrigerant to form a vapour.

Of course if the system that your charging originaly was R134a and there have been no major alterations to the system then you can charge as a liquid by weight (ENGINE OFF) through the liquid line service port.......unless you have a Volvo.

I do understand that R413a does have a small amount of HC in it but once again I tested for flamability (highly scientific) by trying to ignite it with my turbo torch, I still have all my hair so it seems pretty safe to me. There are some companies who sell automotive refrigerants that are 100% environmentally safe (Mainly in the United States ) but these are some form of HC. HC's are illegal for automotive use in the UK and in a number of states in the US. If an evaporator was to burst whilst in service (And they do) I think that that my main concern would be a car full of folk looking like a bad day at KFC! Similarly one of the first items damaged in a front end shunt is the condenser, add heat possible sparks and HC refrigerant and........

09-01-2003, 11:20 AM
The 134A converson kits sold in the US are cheep, effective, legal and easy to install.

Karl Hofmann
09-01-2003, 01:37 PM
Those interdynamics retrofit kits are basicly a bit of PAG oil and a bit of red dye, they're sold to the general public as a quick fix. Their website didn't mention anything about evacuating the system.
There was a discussion a while ago on


The automotive a/c techs on your side of the pond call them "Death Kits"

As you can tell I'm not too keen on "Stuff in a Can", I tried some a/c system sealer in a can a while ago (I try these things before I give them a hard time!) out of 11 vehicles used a guinea pigs, four suffered from blocked driers shortly after, three didn't seal, I haven't the others so I suppose that it worked, but a lesson in cutting corners for me!!! :mad:

09-01-2003, 07:37 PM
Hi, Marc:)
I would have no doubt that UK colleges are behind, far behind what N.Ireland has to offer, don,t forget our biggest export are our young people!
If you fail to get the required grades for a Uni place in Ireland it is quite possible that these lower grades will allow you into a UK uni.
Now that I am finished upsetting the English back to important things, like who is going to buy the first beer. Now being that I am not scottish am not adverse to buying the first beer!:D
(looks like I upset the bosses in Glasgow now!)
When I get some dates I will go a bit further with the beer thing.
now the powers that be have decided that a better presence is required in Ireland, so they have sent me over an engineer to train up to my standards, thus giving me some free time for things like holidays:eek:
Regards. Andy

11-01-2003, 07:16 AM
I read this entire thread and it seems someone forgot to post the info on R413a. I would like to see the specs and approximate cost and places in the US that might sell it please.

Also, GEORGE ALERT! George, how will R406a fair against R413a?

So far, I like the 406A. It works like Hot Shot (R414b), and I haven't had any compressor problems in the past 9 months or so.

I did encounter some compressor failures from the use of R414b though, and a BUNCH from the use of R134a.

Compressor failures were related to domestic refrigerators.

I looked at the EPA site. All I could glean is that the following refrigerants were permitted for use in automobiles:

R12, (SNAP List: R134a, R406a, R414b).

Unless I misread something....?