[sgiitk]

Originally Posted by HKS

Its R12 and R134a. R12 or Freon-12 was the gas originally used in A/Cs.

I missed this. afaik the refrigerant of choice for ACs was R22(CCl2F2) and not R12 (CHClF2). The latter was used in refrigerators. The only AC I know of, which used R12 was the Voltas Crystal 1 tonner from the sixties.

[pratikraveesh]

Originally Posted by sgiitk

Only the new gas is far more susceptible to moisture and corrosive. However, R12 compressors can be modified at reasonable cost to take the new refrigerants.

Could you please explain how a R12 system be converted to R134A? How is the compressor design different for an R12 and R134? I also hear that R134 is being phased out with a new refrigerant, is that true?

[sgiitk]

Th3 design is not really different. R134 is far more corrosive and reacts with water. So special care has to be taken in the materials and handling. I have seen reports where the R12 compressors were overhauled to be made R134 compatible.

[Kamal]

sgiitk,I have read reports / recommendations re conversion from R12 to R134A by experts abroad who caution that extreme care has to taken that not a trace of moisture/mineral oil shpuld be left while attempting the conversion.
Moreover,the receiver/dryer has to be changed & a bigger condensor & evaporator should be fitted to derive full benefit of cooling with 134A.
Two days back, I talked to an A/C shop owner called Manjeet Singh in Lajpat Nagar, N.Delhi re this.He quoted a figure of Rs 8.5k for the job.
On further checking with the Subros own engineer Mr Soni & also their autorised workshop owner called Satnam in Zamroodpur, N.Delhi.I was strongly advised to either go in for a full conversion to 134A ,changing everything except the evaporator @ Rs 17k, or replace the R12 gas with the sustitute Dupont MO49 Plus,which is environment friendly & hence will continue to be available.
I have given a link to Duponts report in my earlier post in this thread, which can be read for more info.
Thus, owners of older vehicles whose A/C system was running on R12 now have a viable, long term alternative which is reportedly even more efficient than R12, without having to change anything in their existing A/C system( provided, of course, its in a good working condition), not even the mineral oil in the compressor.
Another update re cost etc of filling MO49 Plus in south Delhi- yesterday I spoke to Satnam( i've given his mob no in my earlier post in this thread).He stated that if a vehicle owner chooses to bring his own cans of MO49 Plus, he'll charge only Rs 400 for filling it, including nitrogen flushing, leak detection etc.
MO49 Plus is available from Dupont distributors Tayal Refrigeration, Daryaganj, Delhi @ a retail cost of Rs 320 per can of 340 gms.( I required 2 cans for my 1997 model Esteem).If any member wants, I can give the contact nos of Tayal.

[Kamal]

Two and a half moths since I got my 1997 Esteem's A/C serviced from Aman in Okla Phase 3 & filled with Duponts MO49 Plus, which is a relacement for R12.
Superb cooling, this new gas is a perceptibly better refrigerant than the original R12 which it replaced.
Aman has done a great job-BTW, he has an AMC for maintaining the A/C systems of the Rashtrapati Bhavans' fleet of cars, which is evidence of his expertise- and I am one happy driver; earlier, the thought of having to replace the entire system to R134 @ a cost of Rs 20k odd was killing me.

[Captain Slow]

Originally Posted by Kamal

Two and a half moths since I got my 1997 Esteem's A/C serviced from Aman in Okla Phase 3 & filled with Duponts MO49 Plus, which is a relacement for R12.
Superb cooling, this new gas is a perceptibly better refrigerant than the original R12 which it replaced.
Aman has done a great job-BTW, he has an AMC for maintaining the A/C systems of the Rashtrapati Bhavans' fleet of cars, which is evidence of his expertise- and I am one happy driver; earlier, the thought of having to replace the entire system to R134 @ a cost of Rs 20k odd was killing me.

How much were you charged for this ?

[Kamal]

Captain, Aman charged me 1600 for full A/c dismantling & servicing, nitrogen flushing to check for leakage & driving out air/moisture from the system & filling with 2 cans of 340 gms each of MO49+.

[SS-Traveller]

Originally Posted by Kamal

...filled with Duponts MO49 Plus, which is a relacement for R12.
Superb cooling, this new gas is a perceptibly better refrigerant than the original R12 which it replaced.

Thank you for updating us with the information on DuPont MO49 Plus. Wasn't aware of this product till now, and some G-research shows that DuPont also recommends MO49 Plus (as also its other products, MO59 & MO29) for use in home air-conditioning units as well. However, I wonder why MO49 Plus is not accepted for automotive use in the US, despite it being CFC-free.

More information here:
HVAC-Talk: Heating, Air & Refrigeration Discussion - View Single Post - Is MO49Plus™(R-437A) R-12 Replacement any good?

Ease the R22 phase out with ISCEON MO49Plus refrigerant

[Kamal]

SST wrote"However, I wonder why MO49 Plus is not accepted for automotive use in the US, despite it being CFC-free"
Perhaps because the switchover to 134A began much earlier, Year 2000 IIRC, and also because in the US owners change their cars much sooner than in poorer countries like India, therefore, by now most of the vehicles in the US may be already with 134A compliant A/C systems, hence there maybe a larger market in poorer countries for an R12 replacement such as MO49+ than in the US.
I must confess that MO49+ has been a Godsend for a pensioner like me & others who are also on a lean budget.I just could not have afforded a switchover to 134A costing 18 to 20K.
And fortunately it has proved to be a better refrigerant than the one it has replaced.

[lancer_rit]

Hey this is very useful info wrt MO49+ as replacement for R12. My dad's Matiz used R12 for its AC, and now I have a clear idea what to ask for.

[SS-Traveller]

Originally Posted by Kamal

...US owners change their cars much sooner...

MO49 Plus should be the perfect replacement in classic cars which used R12 in their aircon systems, and I'm sure there must be plenty of them in the US.

[Kamal]

Originally Posted by SS-Traveller

MO49 Plus should be the perfect replacement in classic cars which used R12 in their aircon systems, and I'm sure there must be plenty of them in the US.

Quite true.
But I guess, compared to the mass market automobiles, it would be a miniscule percentage, & hence maybe Dupont did'nt bother to go thru the approval rigmarole.

[archat68]

Most of the reputed Car AC service centers and even MASS in Kolkata are not aware of the MO49.
In July 2009 I converted my 2000 Zen to use R134a by spending ~7K. Nobody was aware of it then.

[Kamal]

Originally Posted by archat68

Most of the reputed Car AC service centers and even MASS in Kolkata are not aware of the MO49.
In July 2009 I converted my 2000 Zen to use R134a by spending ~7K. Nobody was aware of it then.

Well, even I heard of this refrigerant only this year, & that too after some net research.
Every car A/C shop that I talked to just said that R12 is just not available anymore, so the only option is to convert to use 134A, either by servicing the compressor & changing the pipes, condensor & evaporator, or by going in for a change of everything barring the evaporator( This is what the Service Head of Subros(na IITian!) advised;even he did not speak of MO49+, though, being in the car A/c industry, he should have been aware of it.I guess they stand to rake in much more money by replacement/conversion than by suggesting an alternative gas!
It was by persistent googling for an R12 replacement that I was able to find out that this alternative is available here.
Then it was a case of ringing up Dupont's Gurgaon office, talking to a marketing guy & obtaining the name/ph no. of their Delhi distributor, ringing uo the distributor to find out which car A/C workshop in south Delhi they were supplying MO49+ to, & then going to one of them,viz Aman Sahil in Okhla Ph3 for the job.
Even my friend who owns a MASS & is an Auto Engr was aware of this!
Every workshop would rather run up a big bill than a small one, so this has remained a well kept secret so far!

[Vikrant Singh]

Hi Kamal,

Whats your feedback on MO49 Plus since your system was charged? Will call u if you could leave a number. Thanks.