Air Cooled Condenser Leakage Problem with R-404A

[RADHAKRISHNARAO]

Dear sir,
we have a wonder problem. :o
we have prepared the condensing unit with air cooled conderser.
Data: Compressor- Semi-hermatic
Conderser- 4 Row -4 fans(sucking type)
comperssor Oil- Fuchs SE-55 Polyster oil.
Gas -R-404A
We provide Liquid line filter,
Suction line Filter.
Suction Accumaltor
Oil separator.
Design Parameters : (-30'C) Evap. temp.
Condesing temp. -(+45'C)
Cold room temp- (-25'C)

Since last six months we have problem with condenser. condenser leak at bottom row at liquid header side inside the fins.:rolleyes:
During this period the condenser leak 7 times. we have replaced the condenser twice.During lekage we found the dischar pressure was 270-310 psig only.:D
and suction pressure- 18 Psig. Oi pressure-105 Psig.
The condenser tube guage is 26.

The palnt is working smoothly but within the month the condenser fails.
whenever the cond. fails we replaced the filters ,oil and charged the New Gas. (too much expansive)
Pl. give some suugestion so that we can slove the problem.

[GXMPLX]

...Pl. give some suugestion so that we can slove the problem.

Congratulations you are one of the few that gives a lot of information in your post.

Unfortunately for you, all you give is IRRELEVANT!

If the system is working smoothly and you change filters and I suppose you don't have acid or corrosion fro inside then the things that cause this are (in general):

Thermal stress usually residual stress due to solder malpractice.

Mechanical stress this could be it, check the base of the condenser is leveled and you don't have a bump in the middle.

Corrosion. There are several types of corrosion electrolytical could be the most common in this case but you must have water, an electrolyte like salt or any other dissolved in water and two different metals like copper and aluminium.

Other type of corrosion is caused by using cleaning materials in the floor or around the area of the condenser that contains for example ammonia? Even if you have smell of NH3 in the air it could affect.
In the case of corrosion you should take a sample of the failed material and look at it under a microscope or take it to an expert. It's very easy to tell.

Vibration is also a possible cause. In combination with residual thermal stress it can byte you in the ...

[chemi-cool]

Very interesting phenomena,
I like that kind of problems.

If its inside the finned area, where about? between the Finns? or at the inside of the frame?

Are the Finns end under the lowest rows or just at the bottom of that pipe?

how long doe's the condenser frame is below the pipes?

Doe's the pipe leak at some soldered point or lengths wise?

doe's the condenser has a "bottom" steel sheet underneath the finns?

What doe's the condenser manufacturer says abut it?

[old gas bottle]

how are the fans controlled ? are they on fan speed controlers or pressure sensors? i can only think that the head pressure is getting to high before the fans are dropping it causing alot of expansion/contraction and movement weakening the coil ends, it does not take alot with the newer thiner wall copper coils, we fitted one this week where the test pressure was only 400 psi!!:eek:

[philfridge]

Since last six months we have problem with condenser. condenser leak at bottom row at liquid header side inside the fins.:rolleyes:
During this period the condenser leak 7 times. we have replaced the condenser twice.



Sounds like your getting faulty condenser coils ? Are they coming pressurised / pressure tested as 7 leaks on a condenser in six months is ridiculus. You need to buy a decent condenser coil as it seems the ones you are buying are leaking like a sieve. ;)

[absrbrtek]

Is the header fan running continuosly or cycling on and off on pressure? Almost all manufacturers nowadays specify that the header fan be on when the refrigeration is running to prevent thermal stressing of the headers.

[smpsmp45]

There is also a possibility of SEBEC effect taking place. Due to dissimilar metal joints & with temp difference, the current causes this type of typical isses. YOu need to check the earthing of the system We had faced similar issue & after struggling many times, we could set it right after proper Earthing. So may be that is the problem.

[RADHAKRISHNARAO]

Thanks sir
the leakage at bottom row which line is entered in the liquid header side between the frame and fins and not at joints but a blow hole in straight pipe.lenghts wise The condenser has G.I sheet at bottom.
The conenser manufacture has told that the 27 guage pipe is suitable for R-404a gas. and they have no idea. there are also warried about this.

we have checked the oil at lab. but it has no such kind of acid particles the PH shows 6.7.

as per your que. the length of pipe below from the pipe is 10".



Very interesting phenomena,
I like that kind of problems.

If its inside the finned area, where about? between the Finns? or at the inside of the frame?

Are the Finns end under the lowest rows or just at the bottom of that pipe?

how long doe's the condenser frame is below the pipes?

Doe's the pipe leak at some soldered point or lengths wise?

doe's the condenser has a "bottom" steel sheet underneath the finns?

What doe's the condenser manufacturer says abut it?

[RADHAKRISHNARAO]

Thanks sir,

There is no vibration in unit.
we are checked the oil at lab. the results are normal the oil PH is 6.7 only.

And there is no Ammonia smell. near the plant.





Congratulations you are one of the few that gives a lot of information in your post.

Unfortunately for you, all you give is IRRELEVANT!

If the system is working smoothly and you change filters and I suppose you don't have acid or corrosion fro inside then the things that cause this are (in general):

Thermal stress usually residual stress due to solder malpractice.

Mechanical stress this could be it, check the base of the condenser is leveled and you don't have a bump in the middle.

Corrosion. There are several types of corrosion electrolytical could be the most common in this case but you must have water, an electrolyte like salt or any other dissolved in water and two different metals like copper and aluminium.

Other type of corrosion is caused by using cleaning materials in the floor or around the area of the condenser that contains for example ammonia? Even if you have smell of NH3 in the air it could affect.
In the case of corrosion you should take a sample of the failed material and look at it under a microscope or take it to an expert. It's very easy to tell.

Vibration is also a possible cause. In combination with residual thermal stress it can byte you in the ...

[RADHAKRISHNARAO]

Thanks sir
the leakage at bottom row which line is entered in the liquid header side between the frame and fins and not at joints but a blow hole in straight pipe.lenghts wise The condenser has G.I sheet at bottom.
The conenser manufacture has told that the 27 guage pipe is suitable for R-404a gas. and they have no idea. there are also warried about this.

we have checked the oil at lab. but it has no such kind of acid particles the PH shows 6.7.

as per your que. the length of pipe below from the pipe is 10".

[RADHAKRISHNARAO]

Thanks sir,

There is no vibration in unit.
we are checked the oil at lab. the results are normal the oil PH is 6.7 only.

And there is no Ammonia smell. near the plant.

[RADHAKRISHNARAO]

Thanks,
We have done proper earthing in plant . the earth shows between natural and earth is 0.00.

[NoNickName]

There is also a possibility of SEBEC effect taking place. Due to dissimilar metal joints & with temp difference, the current causes this type of typical isses. YOu need to check the earthing of the system We had faced similar issue & after struggling many times, we could set it right after proper Earthing. So may be that is the problem.

I would rate this as "most probable".
Please check for galvanic bonding between copper and zinc-coated frame. If so, either remove the bonding, or change the electric potential of the assembly.

[sinx712]

Dear sir,
we have a wonder problem. :o
we have prepared the condensing unit with air cooled conderser.
Data: Compressor- Semi-hermatic
Conderser- 4 Row -4 fans(sucking type)
comperssor Oil- Fuchs SE-55 Polyster oil.
Gas -R-404A
We provide Liquid line filter,
Suction line Filter.
Suction Accumaltor
Oil separator.
Design Parameters : (-30'C) Evap. temp.
Condesing temp. -(+45'C)
Cold room temp- (-25'C)

Since last six months we have problem with condenser. condenser leak at bottom row at liquid header side inside the fins.:rolleyes:
During this period the condenser leak 7 times. we have replaced the condenser twice.During lekage we found the dischar pressure was 270-310 psig only.:D
and suction pressure- 18 Psig. Oi pressure-105 Psig.
The condenser tube guage is 26.

The palnt is working smoothly but within the month the condenser fails.
whenever the cond. fails we replaced the filters ,oil and charged the New Gas. (too much expansive)
Pl. give some suugestion so that we can slove the problem.



105psig -18psig=87psig(fault) it's not good the dif it's entre 30psig to 45psig ( 18psig+45psig it's good for oil pressure) that you are a more quantity of oil in your installation you must find manufacture informations for a juste volum of oil and a type ester huile big sensibelity to!!!wate=acide?,semi-hermitic is very complicate if silencieux in decharge of compresseur .

[sinx712]

105psig -18psig=87psig(fault) it's not good the dif it's entre 30psig to 45psig ( 18psig+45psig it's good for oil pressure) that you are a more quantity of oil in your installation you must find manufacture informations for a juste volum of oil and a type ester huile big sensibelity to!!!wate=acide?,semi-hermitic is very complicate if silencieux in decharge of compresseur not user in this installation .
the cause of your probleme is the oil,your condenseur is big, if is not big your compressor is domag, compressor pumping the liquid not gas.

[apgurgaon]

Dear Radha,

Please check if your CDU is located in corrosive environment i.e. Is there ammonia in environment ( this could be due to presence of a sewage canal, industrial etc )

Please get back on this . I have faced similar prob five years back in a window AC. The reason was presence of a sewage disposal nullah in viscinity.

Best of luck

Anuraag Panchal

[RADHAKRISHNARAO]

Thanks,
There Is No Swage Line Near The Plant. The Plant Is In Open Air Only.
And No Chemical Factory Near This Plant.

[RADHAKRISHNARAO]

Very interesting phenomena,
I like that kind of problems.

If its inside the finned area, where about? between the Finns? or at the inside of the frame?

Are the Finns end under the lowest rows or just at the bottom of that pipe?

how long doe's the condenser frame is below the pipes?

Doe's the pipe leak at some soldered point or lengths wise?

doe's the condenser has a "bottom" steel sheet underneath the finns?

What doe's the condenser manufacturer says abut it?



I WILL ATTACH THE PHOTO FOR YOUR KNOWLEDGE.

[powell]

You state that for the past six months you've had leaks. What about before that? Did the unit run fine for years? History can be very important when solving problems.

Next, if you are replacing the condensers with BOCK factory coils, it's time to get them involved. Have them come to the job site or send the leaking coils to them for inspection.

[RADHAKRISHNARAO]

Dear sir,
This is a new unit only, we have commissioned in Nov.07. we could not get any solution from old condenser. In unit we have replaced the condenser twice and 4 times we brazed the leakage.