PDA

View Full Version : R 404a





Samarjit Sen
21-07-2007, 06:15 PM
I have been thinking about this refrigerant for quite some time.

R 404A is a blend of 44% R 125/52% R 143a/4% R 134a. Now when there is a leakage in the plant, generally people top it up with R 404A.

Now the question is, that while the gas has leaked out, we are not aware as to which of the above gases and what percentage has leaked, and thus by adding another charge of R 404A we are changing the chemical property of the refrigerant, which will lead to malfunction of the system.

My suggestion is that when there is a leakage of 404A or any other similar mixed blend refrigerant, we should completely evacuate the system and charge a fresh charge of refrigerant. Reusing the refrigerant is not proper as I feel.

Any comments or views on the above shall be apprciated.

taz24
21-07-2007, 06:25 PM
Now the question is, that while the gas has leaked out, we are not aware as to which of the above gases and what percentage has leaked, and thus by adding another charge of R 404A we are changing the chemical property of the refrigerant, which will lead to malfunction of the system.



R404a is a Zeotropic blend of refrigerants but the temp glide of the individual components is so small as to make it irelevant.
On another point 404a is used in systems that could hold hundreds of Kg's of refrigerant so replaceing the whole charge when there is a leak would be cost prohibative.

Cheers taz.

paul_h
21-07-2007, 07:12 PM
Just use r507, it's the same blend as 404a but without the r134a.
I'm pretty sure a lot of these blends are only there to lower head pressure and no other reason. eg r404a and r507, only difference is the r134a added. Both have the majority r125 and r143a, where I work they're interchangeable, management doesn't care what you have and whats in there, if it's either, it's good enough.

Some of these blends have *something* added to it just so they can market it.
Eg company 'a' makes r507, company 'b' sees the potential, adds a bit of something so they can sell it under their own name. In these cases it was, "it runs at a lower head pressure, so it's not the same, it's better, so buy company 'b's product!", when all they did was add r134a to it to make the blend more complicated.

Edit: By this I mean don't rush out and buy r507 if you have plenty of r404a. I just mean it doesn't matter too much if the r134a component changes too much after recharging. It will drop pressures a bit if the r134a level is higher, (which is why r507 is favoured in low temp applications), or it will increase them a bit (I'm talking +-20kpa) which is neglible, as plenty of systems designed for r404a are running on r507 around here.

Lowrider
21-07-2007, 09:34 PM
Since R404a is zeotropic, any loss, in either gas or liquid, will result in the same amounth of each of the components lost.

How ever R407c is an other story. It's 404a with more 134a. But since it's no longer zeotropic and has a glide of 10K it mathers where the leak is and how much is lost.

We have a lot of unit's running on 404a and for no appearent reason less problems and leaks on them then the ones with R22, R407c and R134a. I keep the lather three on stock in the van, but never need any 404!?

paul_h
22-07-2007, 04:37 AM
R407c is the same two refrigerants that make up the r410a blend (HFC32, HFC125), but with 52% r134a

Are you getting R410a (used in a/cs) mixed up with r404a (used in refrigeration)?

ralph feria
22-07-2007, 01:44 PM
how about this:
it would depend on if the system is operating and circulating the refrigerant blend.i would think that a static or non circulating system would separate the refrigerants according to their boiling points with the lowest temp one boiling off first. a circulating system would be different as the refrigerants are blended and constantly passing by the leak point. just a thought for your comment.

Samarjit Sen
22-07-2007, 04:13 PM
Since all zeotropic refrigerant are blends of other refrigerants and has a fixed percentage, how can one say that a loss of refrigerant would not effect the chemical properties of the main refrigerant.

This thing came to my mind as I have seen in the case of R 404A, when there is a leakage in the system and when the same is topped up with additional charge, the plant starts creating problems. It does not operate as before. In such cases, I had suggested to take out the remaining refrigerant and evacuate the system and recharge a fresh refrigerant 404A. The performance immediately improved and started working as before. It is my personal experience and as such my opinion.

NH3LVR
22-07-2007, 04:45 PM
Two days ago I was sent to a Chiller System, (in my NH3 truck), because a forklift had broken a fitting on a Copeland Compressor. (Tee installed in the crankcase for pressure controls)
The system produces chilled water through a flooded PHE. The charge is about 250lbs of 404a.
Fortunately the maintenance crew had valved off the Compressor and plugged the 1/4" pipe fitting.
According to them it blew for 10-15 Minutes before they were able to control it.
Not being up to date on 404a I waited until our real Freon guy arrived with a Vacuum Pump and replacement fitting.

We now had several things to consider.
: Should we replace the POE Oil?
: Has the composition of the remaining refrigerant changed enough that we need to recover and recharge with new refrigerant?
: Is the flooded system less sensitive than it would be in a DX system?

My Colleague decided it would be best to start up and top up.
As it turned out we must have been overcharged to begin with as we still functioned fine without having to add. Quite surprising considering how far it blew oil.
I rarely work with 404a am my knowledge comes from the R-12/22/502 days.
Any guidelines are appreciated.

suny
22-07-2007, 05:07 PM
No chance. You have to evacuate the balance available & charge with fresh R404a. If not You have take a sample from the liquid leftover & send to laboratory to check the compositions left, then charge accordingly. But unfortunately that facility is not available for us. This is being done to maximize the profits of the gas manufacturers.

Suny

Samarjit Sen
22-07-2007, 06:00 PM
This is exactly what I had in mind . All this alternative refrigerants to avoid the global worming is basically a mixture of the basic refrigerants and in fixed proportions. I still feel that either we carry on with R 22 or if we have to change for the better then go in for NH3 /CO2.

taz24
22-07-2007, 06:09 PM
No chance. You have to evacuate the balance available & charge with fresh R404a. If not You have take a sample from the liquid leftover & send to laboratory to check the compositions left, then charge accordingly. But unfortunately that facility is not available for us. This is being done to maximize the profits of the gas manufacturers.

Suny

Sorry but I disagree.
R404a has such a small glide as to make it almost an Azeotropic.
Also what you need to bear in mind is the position of the leak.
If it is a liquid leak then liquid will leak at same rate and no effect to the compotion of the refrigerant.
The same with suction gas.
If you have a leak in the suction line then superheated gas has no glide in it so again no affect to the make up of the refrigerant.

That leaves the cond and evap.
If you lose refrigerant mid phase change then that could affect the composition of the refrigerant.
But as I said earlier 404a has such a tight glide that is does not mater.

Cheers taz.

Samarjit Sen
22-07-2007, 06:15 PM
Hello Taz24,

From what you say, that depending on the position of the leak, there is a possibility of the refrigerant changing its composition. The change may be very minute, but a change is a change which alters the property of the refrigerant.

taz24
22-07-2007, 08:42 PM
Hello Taz24,

The change may be very minute, but a change is a change which alters the property of the refrigerant.


True:)

But in context of the system as a whole, would you scrap 60, 70, or even a 100 kg of refrigerant because you lose 10 or 20kg through a leak.
The costs would simply be prohibative.
at £10 to £20 UK pounds for a kg you would not make any profit on your contract if you replace 80kg every time you repair a leak.

I still standby my statement that 404a has such a tight glide that it is almost Azeotropic..
Cheers taz:)

KosmisB
22-07-2007, 10:20 PM
I have been thinking about this refrigerant for quite some time.

R 404A is a blend of 44% R 125/52% R 143a/4% R 134a. Now when there is a leakage in the plant, generally people top it up with R 404A.

Now the question is, that while the gas has leaked out, we are not aware as to which of the above gases and what percentage has leaked, and thus by adding another charge of R 404A we are changing the chemical property of the refrigerant, which will lead to malfunction of the system.

My suggestion is that when there is a leakage of 404A or any other similar mixed blend refrigerant, we should completely evacuate the system and charge a fresh charge of refrigerant. Reusing the refrigerant is not proper as I feel.

Any comments or views on the above shall be apprciated.

Yes I agree, I did it myself and found out that if you change the filling it works, but repairing the leak is wise before you fill up.

expat
22-07-2007, 10:26 PM
With all due respect to your experience Samarjit Sen I would say I side with Taz here in respect to where the leak is.

If you have to charge zeotropic fluids in liquid form it is, as you know, to avoid the problem that would occur if you tried charging in vapor form: as the different gasses in the blend boil off at different temperatures they would enter the system in different proportions, so the original blend would not be true. But even this is because you would be charging the system from a bottle with the plunger hanging above a boiling liquid. Now if you could, hypothetically, boil off all the liquid in a charging bottle to vapor, and then charge the vapor, you could charge with vapor without any risks of the proportions of the mixture being out of line.

So I come back to Taz's remarks:

If the leak is in a place where there is only liquid or only vapor why should one gas or liquid escape faster than another?

Also, as he said when dealing with large charges it would be better, economically, to add 10 kg rather than to change 50 kg.

As we don't live in a perfect world, this seems to be the only way to go.
If there are differences in performance afterwards the customer will neither know nor care as long as you kept your invoice for the repair as low as possible.

11:10 pm...goodnight.:)

Lowrider
22-07-2007, 10:49 PM
This is exactly what I had in mind . All this alternative refrigerants to avoid the global worming is basically a mixture of the basic refrigerants and in fixed proportions. I still feel that either we carry on with R 22 or if we have to change for the better then go in for NH3 /CO2.

Blends are composed off chemicals which have an ozone depletion potential of zero.

Futhermore there are risks involved with using ammonia or carbondioxide in terms of fire and health for starters!

Global warming is a hoax! Invented by commercial men and the government to get more profit!

When someone invented a machine to measure the amounth off ozone they found a "hole" in the ozone layer. Thus we, men that is, made it! Before there was now way of telling if there was a hole or not!

And there are some scientist saying that global warming is a natural phenomena, but we just help it worsen a little! And think abouth it, we've had an ice age and a very hot age before, so why can't it be natural!

Never the less we should keep the loss of ozone depletants to a minimum and use as less power as possible. We should treat the earth in a better way than we are doing now and not cut down all the forests and kill, directly or indirectly, all sorts of animals!

But hey, I'm still a ref engineer and want food on the table so heat up the planet, more work for me!:cool:

Samarjit Sen
23-07-2007, 03:14 AM
Hi Sanderh,

I fully agree with you. To be honest we are being taken in for a ride by the authorities as well as the refrigerant manufacturers.

Keep up the good work.

Samarjit Sen
23-07-2007, 03:19 AM
Hi Taz24, KosmisB, and Expat,

Thank you for your views. I have been eductaed on this point by you all and all the others.

However I still feel that one has to careful when using 404A and unless you know more about 404A or any of the zeotropic refrigerants you should not touch it.

NH3 and CO2 are natural gases. I have never used it, but I am now finding myself more inclined towards the same.

not tamed
23-07-2007, 05:28 AM
I have been thinking about this refrigerant for quite some time.

R 404A is a blend of 44% R 125/52% R 143a/4% R 134a. Now when there is a leakage in the plant, generally people top it up with R 404A.

Now the question is, that while the gas has leaked out, we are not aware as to which of the above gases and what percentage has leaked, and thus by adding another charge of R 404A we are changing the chemical property of the refrigerant, which will lead to malfunction of the system.

My suggestion is that when there is a leakage of 404A or any other similar mixed blend refrigerant, we should completely evacuate the system and charge a fresh charge of refrigerant. Reusing the refrigerant is not proper as I feel.

Any comments or views on the above shall be apprciated.Are you mad,what if i had a leak on a commerical pack and had to decant 120 kilos of 404a ,then tell the store manager his frozen food will be off for a few days while i vac the system back out and recharge the system,oh what to live in a different planet

Samarjit Sen
23-07-2007, 06:26 AM
Hello not tamed,

Yes, I may be mad, but at least I know what I am talking about. Kindly do study about the alternative refrigerants with blends. Under certain conditions you may have to change the complete refrigerant.

The MG Pony
23-07-2007, 06:29 AM
Blends are composed off chemicals which have an ozone depletion potential of zero.

Futhermore there are risks involved with using ammonia or carbondioxide in terms of fire and health for starters!

Global warming is a hoax! Invented by commercial men and the government to get more profit!

When someone invented a machine to measure the amounth off ozone they found a "hole" in the ozone layer. Thus we, men that is, made it! Before there was now way of telling if there was a hole or not!

And there are some scientist saying that global warming is a natural phenomena, but we just help it worsen a little! And think abouth it, we've had an ice age and a very hot age before, so why can't it be natural!

Never the less we should keep the loss of ozone depletants to a minimum and use as less power as possible. We should treat the earth in a better way than we are doing now and not cut down all the forests and kill, directly or indirectly, all sorts of animals!

But hey, I'm still a ref engineer and want food on the table so heat up the planet, more work for me!:cool:


WHOA come back to reality comerade, and learn a bit more about that which you speak! That is nice myth but reality says differant!

Samarjit Sen
23-07-2007, 06:30 AM
I just came accross a book Refrigeration & Air Conditioning by A.R. Trott. It is a very good book on this subject and he has dealt with the Refrigerants in one of his chapters.

This book was sent to me by a good freind of mine, and I wish I could upload it in the forum. Unfortunately it is too big a file. I am sure some of you will be having this book.

charlie
23-07-2007, 01:30 PM
I have a wide experience with R407c that is a refrigerant lot more problematic than R404a to the partial leak (system only partly discharged). In my experience topup the system is OK and you can have only a negligible loss of cooling capacity. Regarding the oil, if the compressor remained with a positive pressure inside no problem. The problem can appear only if the oil is exposed to ambient air for more than 15 minutes. All the refrigerant manufacturer are recommending to recharge completely with brand new refrigerant if you are detecting a system short of refrigerant but in my experience this is only in order to increase the refrigerant sales.

paul_h
23-07-2007, 02:21 PM
duponts own information say r507 will retain a very consistant composition if leakage occurs. So that being said, the only difference between r404a and r507 is the r134a element in r404a, which doesn't cause any harm in r404a system if missing, as I myself have used r507 as a replacement in them.
http://refrigerants.dupont.com/Suva/en_US/pdf/h70013.pdf
Look at a pt chart, there's only a 10kpa difference at 0C when comparing r404a to r507.

Samarjit Sen
23-07-2007, 03:13 PM
As per Dupont, the refrigerant 507 is very consitant. At the same time they recommend that charging should be done in the liquid phase. Now what happens if the refrigerant leakage is from the discharge or suction side. Does it still remain consistant ?

Electrocoolman
23-07-2007, 03:36 PM
I always use R507. Its an AZEOTROPIC and maintains its consistency if a leak occurs. You can charge in both liquid and gaseous phases and top up without any problems. It also has a (slightly) higher capacity than R404a.

paul_h
23-07-2007, 03:49 PM
As per Dupont, the refrigerant 507 is very consitant. At the same time they recommend that charging should be done in the liquid phase. Now what happens if the refrigerant leakage is from the discharge or suction side. Does it still remain consistant ?
Recommend is the magic word there. The word isn't "must" like R410a or r407c. Meaning nothing horrible would happen if you top up a system that leaked from discharge, suction or liquid line.

edit:
What did you do with r502? scap the whole lot every time there was a leak or only topped up with liquid when there was a leak, or happily vapour charge for top ups?
I would not top up r407c or r410a, as I posted in the other thread, it's a decision they may cost the repairer money unless there was an agreement with the customer to get you out of jail. My opinion here differs just because r404a is just r507 with a bit of r134a thrown in. And personal experience has found that r134a in or out makes no difference, ie, they run happy in r507. And r507 doesn't leak in such a way that their components become unbalanced.

Lowrider
23-07-2007, 08:09 PM
WHOA come back to reality comerade, and learn a bit more about that which you speak! That is nice myth but reality says differant!

What's reality!? That over the last milion or so years the earth has heated up after the ice age? And thus we, mankind, made global warming happen?

Man knows little abouth a lot, so because a few scientist with a big mouth say we cause global warming it must be so?

For instance, Greenpeace, who do great work have an account with enough money on it the feed a small african country! They don't need our money any more. Just the annual interest is enough to keep the demonstarations going!

Don't get me wrong, I do think we should treat Mother Earth with much more respect than we do now, but be honoust, because politicians and loude mouth scientist say it's so, doesn't mean it is!

I have a couple of hundred books on global warming and environmental studies (used to be my job, but killing myself is more attreactive than being stuck in some lab or office with so called scientists). All of these contredict each other in one or more ways!

So I know more than enough in my opinion!

Than again, you don't have to agree, it's my opinion!!!!!

The MG Pony
24-07-2007, 05:02 AM
What's reality!? That over the last milion or so years the earth has heated up after the ice age? And thus we, mankind, made global warming happen?

Man knows little abouth a lot, so because a few scientist with a big mouth say we cause global warming it must be so?

For instance, Greenpeace, who do great work have an account with enough money on it the feed a small african country! They don't need our money any more. Just the annual interest is enough to keep the demonstarations going!

Don't get me wrong, I do think we should treat Mother Earth with much more respect than we do now, but be honoust, because politicians and loude mouth scientist say it's so, doesn't mean it is!

I have a couple of hundred books on global warming and environmental studies (used to be my job, but killing myself is more attreactive than being stuck in some lab or office with so called scientists). All of these contredict each other in one or more ways!

So I know more than enough in my opinion!

Than again, you don't have to agree, it's my opinion!!!!!

I was refering to ozone depleation, the way you think they discovered it is not how it did happen, it is beyond a proven fact R-12 and cfc & halone refrigerants are responsible for the damage!

US Iceman
24-07-2007, 06:22 AM
Hey guys, we are getting off topic a bit here. Why not start a new thread on global warming and continue there?

I'll go on record as saying I agree with one of you, but let's pick it up in a different thread please.

Samarjit Sen
24-07-2007, 01:08 PM
You are absolutely right US Iceman. Let us discuss a bitmore on these zeotropic refrigerant

NH3LVR
24-07-2007, 01:41 PM
Why not start a new thread on global warming and continue there?

I agree on a new thread Iceman.
What bothers me is that has become a Political issue, and facts have become secondary. Science is what is important here. Unfortunately in the USA it seems to be a Liberal versus Conservative issue.

New thread by all means!

Lowrider
24-07-2007, 05:00 PM
I was refering to ozone depleation, the way you think they discovered it is not how it did happen, it is beyond a proven fact R-12 and cfc & halone refrigerants are responsible for the damage!

Final Remark on this from me! I always get carried away on this subject!

It's without a doubt that chlorine causes ozone depleation! Chlorine under ultra violet light makes chlorine radicals which in turn "attack" ozone! One chlorine radikal can destroy 2 ozone (composed of 3 oxygen molecules) molecules in one go and many more thereafter!

The only problem I have is the way they built there thesus! But that is a to long and possible to boring story to tell here!

Sorry if I offended anyone!

US Iceman
24-07-2007, 06:36 PM
Here is a thread I started several days ago on the global warming problem. If any want to continue the discussion please feel free to do so there, or start a new thread.

http://www.refrigeration-engineer.com/forums/showthread.php?t=8785

PS. no problems. Just trying to keep the original discussion on topic.

TXiceman
24-07-2007, 08:13 PM
The 400 series are all zeotropic blends and will behave with a glide for condensing and boiling. With this glide you will leak different percentages of the components.

The 500 series are azeotropic and like the old R-512, ir be haves as one refrigerant rather than a blend of several.

Recharging an R-407 or R-404 system will be OK to some degree. 400 series require liquid charging to be sure you charge the proper mixture of rerigerants.

I just avoid the 400 series in all but the smallest of units.

Ken

Samarjit Sen
25-07-2007, 02:41 AM
Dear Ken,

Every one is saying that charging 404A should be in the liquid state. Fine. But what about the leakage in the vapour or gas state. And after that if you top up with liquid 404A, does the composition of the recharged systems remains as 404A or it changes its chemical properties.

TXiceman
25-07-2007, 02:42 PM
Due to leakage in the vapor state, your blend mixture will change slightly. When you recharge, it will be in liquid state and with the correct blend. So over time, the blend mixture will change in the system as it is recharged.

This is why I avoid the 400 series. Problem is no one has really found a suitable azeotropic refrigerant to replace R-22. Our US legislative leaders are too easily swayed or bought-off by the big chemical companies or fall to what ever "greenie-wiennie" bunch that is in the news. Once this gets rolling, no amount of real world data will stop it.

Just don't confuse lawmakers and the general public with facts,when thay can be content to run the country on slanted news.

Ken

Samarjit Sen
25-07-2007, 06:03 PM
It is due to all these, I avoid using any of the zeotropic refrigerants and am still sticking to R 22 which gives a better result.

The MG Pony
25-07-2007, 06:08 PM
It is due to all these, I avoid using any of the zeotropic refrigerants and am still sticking to R 22 which gives a better result.

If I where you then I would seriously consider using R-290 if it is viable! The environmental safety is a big bonus along with its ease of replacement and lower head pressers! It is easy to condense as well!

taz24
25-07-2007, 07:35 PM
Dear Ken,

Every one is saying that charging 404A should be in the liquid state. Fine. But what about the leakage in the vapour or gas state. And after that if you top up with liquid 404A, does the composition of the recharged systems remains as 404A or it changes its chemical properties.


Superheated vapour is total mix, so is subcooled liquid.
The only place where there is likely to be any seperation is when the refrigerant is mid phase change and saturated.

taz.

monkey spanners
25-07-2007, 08:23 PM
The letter after the refrigerant number denotes the glide e.g. R407C will have less glide than R407D
Except R134a (small a = nothing to do with glide) which is not a blend.

Cheers Jon

Lowrider
25-07-2007, 08:53 PM
If you fill a R4XX as a gas, the component with the lowest boiling point will boil out of the liquid and thus the amount of this component charged will be larger! If you are going to empty the entire cilinder of gas it doens't matter if you fill liquid or gas, because all is comming out anyway.

But if you charge just say 3 of 12 kg as gas, the lower boiling component will be larger in mass then in the original mixture!

expat
25-07-2007, 09:42 PM
Samarjit SenIt is due to all these, I avoid using any of the zeotropic refrigerants and am still sticking to R 22 which gives a better result.

Reading between the lines I think you're looking for an R22 replacement that meets your cutomers' requirements without risking ongoing maintenance problems. Because you realize that R22 is going to disappear.

I don't have your experience Samerjit Sen so I will have to say only that 404A has been presented to us and we will have to make do with it.:(

Samarjit Sen
26-07-2007, 04:08 AM
Presented or forced on us. There has to be an alternative. As Ken says who definately has more practical experience that 400 series of refrigerants has problems. Why can not we think in terms utilising NH3 or CO2. Both are natural gas, and by proper application can use them for different applications.

taz24
26-07-2007, 12:05 PM
Why can not we think in terms utilising NH3 or CO2. Both are natural gas, and by proper application can use them for different applications.


I do actualy agree with you on some points.
Natural gases are more environmental friendley and do not suffer with glide.
But economics come into the design equation.
If NH3 and CO2 were easily designed, installed, maintained and cost effiecent then all plants would run with it.
NH3 and CO2 have there own problems they have advantages and disadvantages just like all refrigerants.
If you are looking for one refrigerant that will do all then in my oppinion you will not find one.
We were a lot better off with R12, R22 and R502.
Then Amonia and specialist gasses made up the differance.
But for reasons we all know of the three best gases are banned and other ones have replaced them.
Economics again I'm affraid.:)
I agree with most of what you say. But I feel you are looking for a simplistic answer to a very complex issue.

I have said it before on this thread and I stand by my coments that the glide in 404a is so small that it can almost be discounted.
I have worked with all the refrigerants on the market and I was involved in the replacement of r12 and 502 for some very horrible refrigerants.
For me 404a is a reasonable refrigerant that covers a hugh temp range and is easy to work with.

Just my oppinions from my own personal experience.

Cheers taz.

TXiceman
26-07-2007, 02:39 PM
I have worked mostly on the industrial side on the larger units and limited exposure to the commercial and residential units. I do know the problems I have seen and do not want them compounded on the larger systems.

S Sen is correct n the "forced on us". Here in the states, Dupont did one heck of a marketing job on R-134a to the users. I had industrial customer totally ban all refrigerants except for R-134a as it was termed t "The green refrigerant". If made no difference, they wanted to use R134a on -40 dF 2000 hp systems because corporate policy said to. The corporate policy was set by a bunch of bean counters and lawyers, not engineers or technicians. I spent several years re-educating people to look at other viable refrigerants such as R290 (propane), R717 (ammonia) and CO2.

AS I said, the 400 series will work fine for the smaller units, that you can recharge totally if you have to. but to recharge a system that hold some 20,000# of R22 (4000 HP system), well this is another matter. I had one customer with such a system, that was put in 1989 want to convert to R404 or R407....again a "suggestion" from corporate. After much discussion and looking at good alternates, they decided to "control the leaks much better" or better said, maintain the overall system better, stock pile some R-22 and run the system to it's predicted service life or until at least 2020. So it now is one of the tightest larger systems I believe I have seen. Over the last 5 years of operation, they have not had to add any refrigerant to the 20,000# operating charge.

Also, as I had noted, the 400 series can fracinate and boil off different components at different times. What components you will leak is any ones guess as a systems conditions change trough the day. With this potential problem, I'll just use the azeotropic refrigerants to avoid potential problems, where I can not use a pure component refrigerant.

Long live ammonia and propane.
Ken

suny
28-07-2007, 09:37 AM
Hi everybody who participated in this thread,

What is your final conclusion? After repairing the leak in a system, is it possible to top up wit R404a? Please give a firm answer. Yes or No.

Suny

taz24
28-07-2007, 12:47 PM
Hi everybody who participated in this thread,

What is your final conclusion? After repairing the leak in a system, is it possible to top up wit R404a? Please give a firm answer. Yes or No.

Suny

YES!!!

taz.

Sorry for shouting.:D

paul_h
28-07-2007, 06:59 PM
use r507 instead and not even consider being worried about topping up.

TXiceman
29-07-2007, 04:16 AM
Hi everybody who participated in this thread,

What is your final conclusion? After repairing the leak in a system, is it possible to top up wit R404a? Please give a firm answer. Yes or No.

Suny

Short answer is Yes. BUT, watch your pressures and temps. If you start to drop performance, you may need to dump the charge and recharge.

ken

suny
29-07-2007, 05:44 PM
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

TXiceman
30-07-2007, 01:33 PM
The PAG is a poly alkyl glycol based oil and the ester oil is a POE.

Best to check wit the compressor manufacturer to see which oil type he recommends for the compressor. One point in particular is to watch the elastomers in the system. Wrong oil and the elastomers will swell and then fail.

Last point is DO NOT mix oils. In order to change the oil, you should drain all of the oil from all low points. next charge with a fresh charge of oil and operate for 48 hours and dump this oil charge. Recharge with fresh oil and run for 48 hours. Take an oil sample and have it checked by a lab for contamination from the old oil.

Some times it make take 3 or more oil changes to get all of the old oil out.

I had a fellow put the wrong synthetic oil in an ammonia system and you would not believe the mess. He just changed the oil in the crankcase and when he had a compressor start knocking (Mycom recip). When we opened it for inspeciton, there were globs of a rubbery stugg in the crankcase and he had wiped the rod bearings.

After the rebuild, we flushed the oil system 3 times before we were satisfied the oil was OK. In this case we went back to a straight mineral based oil.

Then the fun started, trying to collect on the bill. We did the work on an open time and material order with an estimated cost up front. We were right on estimated cost.

Ken

Ken

Samarjit Sen
31-07-2007, 05:11 AM
Hi Suny,

As Ken said, please do not mix oil. Moreover it is always better to ask the compressor manufacturer. Lonmg time back I had a lot of problem, as one of my clients of his own added a wrong oil and the entire system just got chocked up. It was a hell of a job cleaning up the system.

suny
31-07-2007, 07:50 PM
Thank you both Ken & Samarjit for you advice and the seriousness of oil getting mixed in the system. Even at any cost I am going to flush out the mineral oil left in the system.

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

“The LTZ compressor 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, you could flush 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 Drier and Expansion valve suitably”.

The MG Pony
01-08-2007, 02:14 AM
Isopropyle alcohol all so makes a very nice cleaning agent!

suny
04-08-2007, 04:27 PM
Hi MG Pony!

Thank you very much for your suggestion to use Isopropyl Alcohol. In general terms here we call for Isopropyl Alcohol as Surgical Sprit. How about, if I use Methyl Alcohol as cleaning and flushing agent. Please give your advice.

Suny

Samarjit Sen
04-08-2007, 04:46 PM
Hi Suny,

Why are replacing the Bitzer open type with Maneurop LTZ compressor. What is the temperature required for the Evaporation and the Condensing ? Did you have any problem with Bitzer open type compressor. Could you please give me some details as I would like to do a bit of study on the same.

suny
05-08-2007, 04:36 PM
Hi Dear Samarjit

I am sorry u have misunderstood, that I am going to replace a Bitzer with Manuerop. The system I am going to install ran with a Bitzer open comp on R22. I used t Bitzer for a mobile truck. The Manuerop I had as a spare comp which I am going to utilize for t ice cream storing room with a temp of -30 deg C. If u need any info about t freezer truck I could give details. Further all my replacments are done either with Bitzer or Manuerop.

Suny

Samarjit Sen
05-08-2007, 04:59 PM
Suny how are you. Do you think Maneorop sealed compressor would be able to attain the temperature of - 30oC for the Ice Cream Room.

A semi hermetic of Bitzer or Dorin with Vapour injection would have been more suitable. You would be requiring a Te of about - 35oC.

I shall definately seek your assistance for the truck refrigeration system.

With all my best wishes,

suny
07-08-2007, 06:35 PM
Dear Samarjit

Yes, I am using Manuerop compressors to maintain a cut out temperature of -30 deg C in my cold rooms. It is the LTZ series with R 404a. Even the manufacturers recommend that we can go up to - 40 deg C Te. They have introduced another series NTZ a multi refrigerant compressor. I have not used it yet. There is another advantage the prices are cheaper than the semis.

Suny