R 404a Compressor

[suny]

Hi! US Iceman, Peter_1 & members

Can you all give me an advice on whether I could charge R22 for a Manurop LTZ series R404a compressor after changing & flushing Synthetic oil in it and re-charging with Mineral oil to the compressor? If so will there be any damage to the compressor & any drastic reduction in the efficiency of it. At the moment I am fed up with this 404a.

Suny

[monkey spanners]

R22 if fine with ester oil. As to whether the compressor and condenser matched for R22 i don't know. If it is listed as being able to run on R407C it should run on R22 ok. I'd check with Maneurope if i where you.
The real question is why are you fed up with R404A?

Jon

[paul_h]

You won't need to do a oil change, r22 runs on ester oil OK. But the LTZ compressor is design for low temp applications, -20C evap, and correct me if I'm wrong, but r22 doesn't like going that low, the head pressure gets to high.

[US Iceman]

If you can find the ratings for this compressor with R-22 compare that to the R-404a performance at the same operating conditions.

If the capacity and power input are within say 10% of each other you should not notice any appreciable difference in operation.

Theres nothing wrong with using R-22 for low temperatures if the system is designed properly, but the discharge temperature can get fairly high.

[suny]

Hi Everybody

Thank you all for giving your comments. I am sorry everybody. I forget to tell you all earlier, that on the system I am going to install, the evaporating side there is Eutectic plates which worked previously with a R22 system with mineral oil & at Te -40 deg C. The problem I am facing is that it is little bit difficult to drain out the mineral oil in the Eutectic plates. This is the main reason I want change the ester oil into mineral oil in the compressor which I have an easy access. Please let me know the followings:

1. If by any chance if the mineral & ester oil get mixed in the system will there be any failure?
2. Can I use Mineral oil to run the Maneurop LTZ compressor?
3. What will be the effect due to difference in mass flow between the two refrigerants?

Daer Jon:
The LTZ series is listed with R 507. We are a developing nation. In my freezer trucks it is very difficult to install a R404a system due to bad road conditions and very frequently we find system failures due to leaks. For stationery application I am using R 404a for low temp.

Dear Paul h:
Yes LTZ is designed for low temp. applications but I am using R22 for low temp. with an additional cooling fan for the compressor heads or with CIC system for Bitzer. Those are working perfectly without any problem for so many years.

Dear US Iceman:
Yes I found out the rating but it is available with R507 not with R22. Working condition at 40 deg C Tc, -30 deg C Te for R 507 & R404a are both same. Cooling Capacity 6500 W, Power 5400 W. As per your advice with regard to the discharge temperature & as per the manufacturers of the Maneurop compressors are designed to withstand liquid flooding back. Even they have advice us to remove the suction accumulators of the system. As such what will be your opinion if I give HP liquid through a small capillary tube to the suction line to reduce the discharge temperature? Please give your expert advice on this matter.

Suny

[BESC5240]

First some 'official answers':
- If the condensing temperature is higher then 30°C, LT compressors are not allowed to run on R22. (too high discharge temperature).
- It's not allowed to run Maneurop compressors with R22 and POE oil. (the danger lies in the combination of humidity, ester oil and Chlorium atoms)

Some 'unofficial answers':
- If you're able to control the discharge temperature by a controlled injection (preferably electronically controlled) you could give it a try (without any warranty from the factory), but I think it will not be possible with a Te at -40°C. A fan is of no use here.
- capacity can be estimated based on R404a data and R22 logP/h diagram

[US Iceman]

BESC5240 provided the information I was hinting at. You have to watch the cmopressor application envelope. Very low temperature R-22 will have very high discharge temperatures in a single stage compression application.

Even with liquid injection, I suspect the discharge temperature will still be too high.

[old gas bottle]

put my two bits worth in, why would you want to remove the suction line accumilator when they can only be of a benifit on a low temp system that will certinly be flooding back at one time or another,manurope will take some liquid hammer but i would not push that issue as its a compressor not a water pump and washing the oil out of it is a distinct possability aswell as other liquid related problems, R22 does run out of steam at low temps as opposed to R404A but try it,you can allways convert back if you get problems,i would stick with synthetic oil and change it after a couple of days or go for a good semi synthetic.

[suny]

Thank you very much for all, giving advices on the above. I am going to use this LTZ Manuerop compressor for stationery application to store Ice Cream & on your advice I am going to flush out the mineral oil that is available in the eutectic plates even it is bit difficult to perform & will be charging R404a & ester oil. Thanks again for every body there.

Suny

[suny]

Hi everybody who participated in this thread,

My technician told me today that there is refrigeration oil in the market with brand name “PAG” which can be used on system that ran on mineral oil. There is no injury to the system if we charge the R 404a compressor in my case Manuerop with PAG oil instead of ester oil. Please give your opinion.

Suny

[monkey spanners]

PAG oil (polyalkalineglycol spelling?) is used in car air conditioning compressors and is quite expensive. it is more hydroscopic then ester oil and personally i would not use it in this application, though i'm no expert.
Ester oil will mix with mineral oil. It was developed to do this so that old R12, R502 systems could be flushed of the old mineral oil by changing the compressor oil three sucsessive times with a suitable run time inbetween and then finally another oil change and refrigerant change to R134a,R404A as aplicable. This was before we had all the drop in replacements. I did a lot of the oil/refrigerant changes (retrofits) with Castrol in the UK (for my old employer) when they where developing their icematic ester oil.
Maybe you could run the system on R408A which is a drop in for R502 and should work with mineral or ester oil, for a short while and use this with three or four oil changes to reduce the mineral oil percentage to an acceptable level, and then change to R404A, effectively you would be using the R408A to flush the old mineral oil out of the evaporator. You can get oil testing kits to check for mineral oil concentration.
I think R408A is not a long term solution, here in the uk at least as it has a HCFC in it and is due to be phased out in 2010.

Cheers Jon

[The MG Pony]

Hi everybody who participated in this thread,

My technician told me today that there is refrigeration oil in the market with brand name “PAG” which can be used on system that ran on mineral oil. There is no injury to the system if we charge the R 404a compressor in my case Manuerop with PAG oil instead of ester oil. Please give your opinion.

Suny

Unles your compressor is open shaft it will distroy your system! Pag is unsuitable for semihermetic and hermetics. Along with this it is very sensitive to chlorin, so any traces of old R-22 or any chlorine containing refrigerants will break it down.

[suny]

Dear Cheers Jon/MG Pony

Thank you for your advice. I will follow it. Regards

Suny

[suny]

Thank you Cheers Jon & MG Pony for your advice. How about Acetone to flush out the remaining Mineral oil in the Eutectic freezer plates.

Furthermore for your information herewith I am attaching the comments made by the manufacturer’s representative. I Quote:

“The LTZ Compressor (http://www.refrigeration-engineer.com/forums/glossary.php?do=viewglossary&term=60) is not suitable for R22 even after oil change. Basically, we had to discontinue the CFC/HCFC range for low temperature application long back in the late 90s, due to new regulations worldwide on the (limitations on) usage of CFC and HCFC.

After dis-mantling the Compressor (http://www.refrigeration-engineer.com/forums/glossary.php?do=viewglossary&term=60), you could Flush (http://www.refrigeration-engineer.com/forums/glossary.php?do=viewglossary&term=180) the existing system with R141b or any solvent (unleaded petrol could be a good choice - but, please maintain safety). Please do not use CTC solution as it has chloride content although it is a good solvent. Solvent will clean the system of all traces of any mineral oil leftover from the previous installation. Then, you could use the LTZ88 with R404A or R507.

I hope you have correctly selected the LTZ88 to replace Bitzer open type. In case, you do the above, please remember to change the Filter (http://www.refrigeration-engineer.com/forums/glossary.php?do=viewglossary&term=171) Drier and Expansion valve suitably”.

Suny

[shanman]

Hi suny,

just a quick question , have you tried using R507a? R404 is a terrible gas to work with as you always have to charge with liquid as it is a mixture of 3 gases.

[shanman]

Hi suny,

have you tried using R507 gas instead? R404 has to be liquid charged as it is a mixture of 3 gases.

[suny]

Hi Shanman

I haven't used R 507. How is the performace of it?

Suny

[monkey spanners]

Hi Suny
I've not used any of the flushing methods you mention. With the systems that i've converted from cfc to hfc we ran the system as normal and changed the oil from mineral to ester, after a suitable run time had passed we changed it again etc. We found that four oil changes was sufficient in most cases. This had the effect of diluting the mineral oil concentration to below 3%. Then we changed the refrigerant.
In a few cases (due to system loosing a complete charge) we have changed the oil and refrigerant on the first visit and then followed up with three more oil changes (this is similar to your situation).

This was mostly with prestcold/copeland compressors.
I don't have much experience of maneurop compressors and changing to different refrigerants.

Found this on the Dupont web site, R422A/MO79, a hfc based refrigerant that will cope with mineral/ester mix. If your compressor can run on this the the oil mix should not be a problem in my opinion.

http://www.refrigerants.dupont.com/Suva/en_US/products/isceon79.html

Jon