Re: Change from R22 to R404A
my view run away quickly a lot of work in a day for one man to change you would firstly sea if comps compatiable with r404a if they are you need to change all tevs and match orifices change oil and drier adjust all lp and hp switches but r404a pressures more than 22 so do you really want to put that kind of extra pressure o n a old system do you have drop ins for 22? is this whycustomer wants to change?
Re: Change from R22 to R404A
Hi,
I would be careful that equipment is suitable, as the density of R404a differs from 22, pipe size selections may differ and often require increasing.
If you don't check then you may experience flash gas in the liquid line and suffer with temperature, poor efficiency. Also suction lines may incur an increased pressure drop and reduce overall compressor capacity, Suction pipe work must also be checked for correct velocities for satisfactory oil return.
There are a number of other complications but this is a start.
Hope this helps
Re: Change from R22 to R404A
I have changed over a few packs ,as the guys said oil ,driers ,valves etc make sure to fit suction filter if it has been removed as 404 appears to have cleaning effect on older systems . the only real problems we had were seals been eaten by new gas/oil on some of the older solenoids and shut off valves.
Re: Change from R22 to R404A
Quote:
Originally Posted by
kerrcell
Guys,
Can across a client that wish to change centralina from R22 to R404A.What should I start with.
I thought of compressor oil change( of three ) from POE to ??? suggestions please.
Compressors are Bitzer.
Liquid line cartidge filer core.
Expansion valves are Danfoss TXE5.Liquid line entry to is flare type,but outpu to evp is brazed.Should I consider replacing only the orofice to a specified type ?
The pipes after reclaiming all the refrigerant needs to be cleaned.What sould I use as a cleaning agent ?
My problem is that this centralina feed 3 upright freezers and another three open type freezers.Client is only allowing a day,probably a public holiday to carry all,which I am seesing impossible.Any views ?
Kerrcell,
Check the shaft power absorbed by the compressors, if the compressor is open type. If the Bitzer compressors are semihermetic so normally the motor is enough to work to R404A as the same motor is used.
I would do in this way (just a resume):
phase 1 » Change the mineral or AB oil by POE still with the plant working with R22 for a couple of days. Change again past 1 or 2 days. Use the refractometer to see if the mineral oil concentration is already low. The POE is a cleaning agent.
phase 2 » Plant have to stop. Evacuate R22. Change the filters and replace the orifices, normally you have to select one or two orifices above. If you are already on the orifice nș4 change the valve body. If you maintain the same TEX body then only the thermostatic element. Also you should change all the elastometers (from the seals, o'rings).
Pressure with N2 to see any leaks. When you blow out the N2 it will help to push out dirty.
Deep vacuum. If you can't wait to long use multiple vacuum pumps.
Charge with R404A, start the plant and make operating tests
This phase can long 2 or 3 days. See if the Client can stop during the weekend
Phase 3 » Past 2 or 3 days see how the oil is and changed if necessary. Change once again the filters. On these periods the plant doesn't need to stop totally and if does it is only by a brief moment.
Attention:
1) The mass flow with R404A is much higher. Important extra pressure loss specially on the liquid line will occur which will drop the capacity on the TEVs. May in some parts the liquid line be changed. However if the system has a good subcooling you don't have to hurry about.
2) Also the discharge line extra pressure loss will occur, resulting in even higher discharge pressure.
3) See if the liquid receiver and it's own safety valve are capable to stand the new higher pressure.
Re: Change from R22 to R404A
I would consider using R-507 and not R-404.
All the above, the same, only refrigerant.
Clear and simple explanation Sandro!
Re: Change from R22 to R404A
Good Chemi,
I also like more R507 because of the azeotropic properties. The capacity is a little higher, little better COP, less discharge temperature, albeit the pressure is a little higher. Unless the Client really want it. However it could be mixed with R404A with no problem.
Re: Change from R22 to R404A
Hi again Guys !
It seems a good topic.
Well to update,client called someone in and was given the idea to change to R404A.I explained that since there was no major breakdown would leave everything as is.But !
Now there should be no problem of using R507 instead of R404A as this have been the client's suggestion only.
My main concern is that the client is thinking that in a day can clear all,which is not the case as we all know.3 of the uprights need also to change the txv(TEX5),R22.Another open freezer has an electronic controlled txv solenoid OKVO,this has also to be change.
Now the last comment from chemi-cool suggests using R507.I would ask now besides changing the oil ,would still have to change txvs/orifices,filters,etc... ? Compressors are semi hermetic.Condensers are air cooled,and since there are three compressors,there is an oil header.Also compressors has oil regulators.Kindly update.
Re: Change from R22 to R404A
why not install a drop in? what is the availability of 22 there
Re: Change from R22 to R404A
R22 is short of supply and we are using the R422D as topping or replacing.Price is also changing all the time.I recommended to client that till there is supply of R422D,there is nothing to worry about.The change in price still less than to take all this work to change all txvs,filters,oils,etc...Also he is expecting to be in shortest time possible since it is a supermarket.I hate working with that pressure as if there's mistakes,I will be the one praying on my knees infront of the equipment ! Also doubt payment as well,reasoning facts !
The fact there was the suggestion of R507,is it possible to reclaim all R22,clean all,change oils,and then simply fill in ? I doubt it is that simple,again dont' want to spend nights in this supermarket !!
Re: Change from R22 to R404A
About R422D There may be some problems concern with oil return if the pipe is long and complex. You should mix some POE. Also the filters and elastometers should be changed. Decrease of capacity should be expected.
The % of hydrocarbon dissolves easily with oil, so watch out the oil changes.
Re: Change from R22 to R404A
Sandro,
Plant manager states that system already running on POE.My concern is the possible start of gasket and seals leaks during time,if not instantly.Some one also said that R422D tend to clean older systems,that is another concern,and compressor/s oil consumption is the wost on of all.So putting all on a scal,thinks that client should stick to running the system on the R22 and if there's a major leak would change to R422D but would not be wise to make expenses,unless there are problems in for the moments.
Re: Change from R22 to R404A
Quote:
Originally Posted by
kerrcell
So putting all on a scal,thinks that client should stick to running the system on the R22 and if there's a major leak would change to R422D but would not be wise to make expenses,unless there are problems in for the moments.
I also agree with you but I would advise the Client to as soon as we can stop the plant for 1 week (holidays for example) he order the retrofit. Even using the R422D the things can be resolved on a "snap of fingers". Don't you agree?
Re: Change from R22 to R404A
Why doesn't the Client uses the R422A? It's more indicated for low temperatures...
Re: Change from R22 to R404A
It is not used here sandro. But best thing as you said,prepare and keep in stock so that when there is abreakdown,will change to R422D.
Re: Change from R22 to R404A
Quote:
Originally Posted by
kerrcell
It is not used here sandro. But best thing as you said,prepare and keep in stock so that when there is abreakdown,will change to R422D.
Why isn't used there?
Re: Change from R22 to R404A
Quote:
Originally Posted by
Sandro Baptista
I also agree with you but I would advise the Client to as soon as we can stop the plant for 1 week (holidays for example) he order the retrofit. Even using the R422D the things can be resolved on a "snap of fingers". Don't you agree?
Sorry I meant "Even using the R422D the thing cannot be resolved on a snap of fingers".
So as soon as the Client has availabity to stop for 1 week the plant to make the retrofit I think he should do it.
Re: Change from R22 to R404A
Here smaller country,smaller investment ! Mostly used is the R415,R404A,R134a still. Air conditioning R407C and R410A.
I shall advise client that there is a weeks job involved if he is to do the change.
Thanks a lot.
Re: Change from R22 to R404A
What if I collect all R22 and charge with R422a or D using same expansion valves ? Is it possible ?
Re: Change from R22 to R404A
I've heard that many people do it simply in that way...after all it's a drop in :) . The TEV valves can be the same. The problem are the elastomers of the seal that can leak. Take that risk you wanted. But I advise to make a good vacuum and also change the filters...the filters you can change quickly.
Re: Change from R22 to R404A
Will stick to it and update you later what happened,thanks guys. ;)
Re: Change from R22 to R404A
probably acid formation of the ester oil ....... ester oil is the derived from an acid which releases water + ester oil ........... the chemical process is reversible and therefore a strong possiblity of acid formation in the presence of moisture .............your oil ph could be 4 or around .
IF YOU CAN SEND ME A pm on ddk0123@gmail.com , i can send tou guidelines for R-22 to R0404A conversion
