How to change (retrofit) a quite a meat cooler with R12 to r134a system.

[Ray Vella]

I have a friend of mine who is a buthcer & he has a quite but in very good shape old wooden made cooler.the system is run with R-12 which is absolete ofcourse! The motor-compressor is a semi hermetic type which is still very efficient.Now a leak has developed & I can ask for assistance if it is possible to just change the oil of the compressor & the automatic expansion valve to an R134a one,rather then to change the old but very still efficient compressor also?

Thanks for any help !
Ray

[monkey spanners]

Generally yes, i've done quite a few R12 to R134a conversions, usually we change the oil and run the system for a few weeks, or maybe until the next maintenance visit, then repeat the oil change, wait again, and repeat the oil change, and on the fourth visit, change the oil again, replace the drier, and replace the R12 with R134a, you may not need to change the expansion valve, often the can be adjusted for correct superheat. If the system has a solenoid i would strongly advise you to replace it as well at this time as often the combination of R134a and ester oil will cause them to start leaking.

On a few occasions we had to change the oil and Refrigerant on the first visit (due to system leak such as in your case), in these cases we would go back the next day to change the oil again, and so on until the system has had four oil changes total. We found four changes was enough to get the mineral oil percentage low enough. If you take this route it may be worth getting the customer to keep an eye on the oil level in the compressor between your visits just incase there is poor oil return due to the residual mineral oil in the system.

Jon

[Peter_1]

How old is this unit? given the fact it's still R12, I guess 20 years or older.
IS it a hermetic? If so, how will you change the oil?

[icecube51]

i thought there was a problem whit the oil in the semi-hermetic compressors. the motorwindings cant stand the acid of the polyolester oil?
the have an easy burn out diu to the fact that the POE oil takes the protectection of the windings of.

Ice

[monkey spanners]

i thought there was a problem whit the oil in the semi-hermetic compressors. the motorwindings cant stand the acid of the polyolester oil?
the have an easy burn out diu to the fact that the POE oil takes the protectection of the windings of.

Ice

We did loads of prestcold/copelands, a few Fridgidaires without problem, infact we never had a problem with the compressors as such, even when we did hermetics.
The only problem we did have was with Maneurop comps which would wax up the txv's afterwards, often needing a new txv and orifice.
I beleive it is due to the wax used to lubricate the windings as they are wraped round the motor during manufacture.
There can also be problems with high magnesium content to in some compressor components but again we never saw any symptoms of this in over 200 conversions.

Jon

[lana]

Hi there,

Just add to the other's statements :

1- Change the mineral oil from the crankcase to synthetic one for R134a.
2- Run the system for a while. BE CAREFUL do not change the refrigerant. R12 must still be in the system.
3- After a while change the oil again.
4- Repeat this until the oil contamination is below 1%. Use a paper indicator for this purpose.
5- When oil is free of contamination then change the oil to a new synthetic one and now you can change R12 to R134a. Also change filter drier and TEV nozzle.

Be aware that if you keep the same compressor you will have nearly 7-10 % less capacity with R134a.

Cheers

[Ray Vella]

Thanks guys for your promptful assistance ! I think that I found a much easier solution ...probably in the local market thee is a product that is mostly used for automotive ac; this is a kit of oil mixed with R134 a. But to be honest i haven t yet bought it ,so as soon as I will get it then I will let you all know about it !

Thanks again folks !!

[chemi-cool]

There is a special flushing agent that cleans the system almost totally from oil. [forgot the name]
You can get it at any refrigerant supplier.

Apart from that, I'd go with Lana explanation.

[Ray Vella]

Sorry guys it took me long for replying to this problem but I was very busy lately..! the solution for retrofitting an R-12 system to R-134a one is HERE!!!! I purchased a kit called: EZ form INTERDYNAMICS from Polar co.ltd. Malta. this works as a retrofitting agent , all you need to do is just discharge / reclaime the old r-12 out of the system, change the filter drier don t have to change the AEV (left it in the system) & vacuum down.
I applied 2 cans of this oil/R-134a mixture in the system & finally added R-134a to top up enough the new charge.Beleive me this method works !!!!take my honest word for it :
EZAuto air-Conditioning recharge & retrofit KIT !!!! take my word!!! In the kit there is also a demonstration dvd to illustrate the retrofitting method!!

[redmancraig]

i wouldnt retrofit to 134a im not a big fan of the retrofitting when i dont have more work then needed just get the refrigerant r 414b its a good drop in refrigerant for r12 its mineral oil compatible so no work remove the r12 fix the leak and drop in the 414b and your done no worrying about the oil

[Magoo]

Try a drop in first, save the greif of call backs. R406A here is a fairly good option. Once the old clanger finally dies start with a total new system.

[Peter_1]

Sorry guys it took me long for replying to this problem but I was very busy lately..! the solution for retrofitting an R-12 system to R-134a one is HERE!!!! ....Beleive me this method works !!!!take my honest word for it

Believe ME my friend we will here each other within some months, a year.

[wsdjh]

Thanks guys for your promptful assistance ! I think that I found a much easier solution ...probably in the local market thee is a product that is mostly used for automotive ac; this is a kit of oil mixed with But to be honest i haven t yet bought it ,so as soon as I will get it then I will let you all know about it !

[tonyhavcr]

Sorry guys it took me long for replying to this problem but I was very busy lately..! the solution for retrofitting an R-12 system to R-134a one is HERE!!!! I purchased a kit called: EZ form INTERDYNAMICS from Polar co.ltd. Malta. this works as a retrofitting agent , all you need to do is just discharge / reclaime the old r-12 out of the system, change the filter drier don t have to change the AEV (left it in the system) & vacuum down.
I applied 2 cans of this oil/R-134a mixture in the system & finally added R-134a to top up enough the new charge.Beleive me this method works !!!!take my honest word for it :
EZAuto air-Conditioning recharge & retrofit KIT !!!! take my word!!! In the kit there is also a demonstration dvd to illustrate the retrofitting method!!

Ck I believe you But you should believe me it will not last it will be a bad burn you will be back.
What I do on old small systems is is change the condenser unit this will take 80`/. of the oil then blow out the lines w/ nitrogen hook up the system run it w/ 134a and test it it should be good rf not I change the oil to its good.

(Peter_1
How old is this unit? given the fact it's still R12, I guess 20 years or older.
IS it a hermetic? If so, how will you change the oil?)

You remove the compressor and turn it up side down
or use a mini oil pump cut the suction line sick the tube in and pump the first one is the fastest.

[Peter_1]

I know how to change oil but a hermetic on R12?
Ready for scrap, not worth spending 1 minute to retrofit it.
In the time you have done all this (remove compressor, remove oil, change oil, rinse, flush a second time, remount compressor,vac. it) my new unit will be already installed and I can give warranty.

[icecube51]

it is not always the money that they worry about, it is letting go the old crap who has being nice to them for over decades.

someone has to steel it overnight, so they are obligated to put a new one in place.

Ice