Retrofit

[Geofridgee]

I have a system that needs retrofitting. It is currently running on R12 with suniso 3gs oil. If I retrofit with R409A all I need to do is reclaim the old refrigerant and I am going to drain the oil and replace with fresh but that should be it.... Shouldn't it ?

Do I need a new tx valve ? Or to replace the orifice ?
Anything else....

[The MG Pony]

MP49, No new oil, txv should work well.

[Sledge]

I would try using 408a if it is available. I am having a lot of success with that, and according to the lierature there are a lot of pluses.

better performance, higher oil miscibility, less corrosive...etc

I have encountered a few systems with 409 and plugged cap tubes. I am thinking it is more corrosive and is dragging all the crap it can into the cap tube.

[Geofridgee]

It is a trane compressor- fairly large system, thanks for the tip on 408A. I don't deal with alot of equipment of this age and the retrofit is something a little foreign to me !

[Samarjit Sen]

For 409A you change the oil and check the TEV superheat setting. 409A has a Boiling Temperature of - 34 Deg C and a Temp.lide of 8.1 K

[TIGA]

Hi,just do as sledge said but after reclaiming the gas and oil as well. fix every thing back top up oil and charge with the requierd gas.Run the system for about half an hour,stop the machine retrofit again then do the final charge.

[monkey spanners]

I've been using R413A (R49) in ice builders and car ac also. I think that R409A has R22 in it and so will not be available when R22 is no longer made.

Cheers Jon

[The MG Pony]

Like I said, 10 out of 10 Techs I've listend to talk about MP49 where orgasmic over it. So It seems to be the prefered for R-12 retrofits.

[Samarjit Sen]

Bitzer has a very good document on retrofit of compressors with various refrigerants. If you visit www.bitzer.de you will and go their documents section you will find the file Report. It is a very good reference document for retrofitting.

[charlie]

R134a should work fine but for sure you'll need a different type of oil (ester oil).

In order to avoid acidity in the system you must have maximum 5% of residual mineral oil left in the system (and isn't easy to check it you must have a specific tool called "refractometer").

Expansion valve should be OK.

Good luck.

[lana]

Hi there,

If you want to retrofit remember not to let R12 out first.
You need to wash the system from mineral oil. This is done by changing the oil to the synthetic one (which is compatible with the refrigerant used ). If you choose a refrigerant which needs synthetic oil then this is the way :
1- Evacuate the oil from the crankcase as much as possible.
2- Add correct synthetic oil in the crankcase.
3- Run the system for a while.
4- Change the oil again.
5- repeat this until the oil contamination is below 1%. Remember synthetic oils have a cleaning and washing capabilities because they have alcohol in them.
6- When you are sure the oil is clean then you can recover R12 and charge the new refrigerant. Also at this stage you have to change the oil to a new and clean one once more.
7- According to the capacity of the system check the TEV. For sure change the filter to a correct one.

Good luck
Cheers

[Sledge]

I would try using 408a if it is available. I am having a lot of success with that, and according to the lierature there are a lot of pluses.

better performance, higher oil miscibility, less corrosive...etc

I have encountered a few systems with 409 and plugged cap tubes. I am thinking it is more corrosive and is dragging all the crap it can into the cap tube.

I am sorry, blame this on weeks of 18 hours days, in a scalding hot bakery, and add a pissed off wife. I am usually not this stupid...I dont think.

409 is a R12 replacement, and 408 is an R502 replacement.

I will save my posts for after I get some sleep.

[goodguy]

The MG pony, Do you mean MP39(401a)? If you mean what you say, i would like to know some more info on it.
Cheers

[goodguy]

I've been using 426a and have had good results. It is also a HFC.
Good luck

[The MG Pony]

*Slaps head* Ya MP39, I all ways call it 49 for some reason.

[goodguy]

Ah, no big deal. If that is the worst thing that happens, your doing very well.

[Geofridgee]

Thanks for all the feedback. I have a few years under my belt but this industry is so varied that I learn something new every day- forums like this and the helpful people willing to share their knowledge really make life much easier.

[paul_h]

I was doing retrofits to r12 and r500 systems back in the 90s, we never did any less than three oil changes, plus a drier change. We never bothered changing the TX, just checking and setting if neccesary.
The gases available then are probably different to today though, except for r134a that is.
We had quite a few crankcase seal failures after charging 134a into a r12 systems for some reason though

[pendlesteve]

R408A is a drop in for R502
R409A is a drop in for R12
Both contain R22
R413a is a very good performing drop in, does not contain R22, but do check & adjust the tev superheat.