Compressor immersed in Chiller water

[balapmurugan]

Need technical support for York YR 300TR water cooled screw compressor.

To attend the sliding valve stuck up issue, the R134a gas was unloaded using compression vacuum pump upto 5"Hg column. Next day morning it was noted that chilled water got mixed in the gas chamber and the motor got immersed in water due to evaporator tube damage and leak. THe chiller plant was running in good condition until the plant was stopped.

a) What are the possible reasons for the evaporator tube damage. The plant is about 5 yrs old and the bottom row extreme tubes in the evaporator section got damaged. While removing the gas, chilled water circulation was done at 15 deg.C, 4kgf pressure.

b) We would like to know if anything went wrong while unloading the gas ? Checked for any water particles in the last cylinder in which the gas was unloaded by transferring to another cylinder and no water was found.

c) What is the best procedure for improving the motor megger value without removing the motor. At present about 1 Megohm is the value. Is it advisable to pass hot dry nitrogen through the gas charging side and what is the recommended max temperature of the gas to minimize the moisture removal time. Whether the bearings need to be replaced ? What is the safest megger value before restarting the compressor motor.

d)Is it necessary to rewind the compressor motor and the bearings just they got immersed in water ? Will the life of motor and the bearings be drastically reduced just in case the plant starts normally ? Will there be any issues such as carbon contamination / accumulation in the gas chamber if the motor is not rewound.

e) Any one can provide the cross-section drawing of the MaxE YR chiller compressor motor ?

f) Is there any York chiller compressor maintenance manual available in soft copy form. Can anyone post it ?

Seeking expert support from the team.

Thanks !

[NoNickName]

Kiss it goodbye. Don't even bother.

[The Viking]

From reading your post I assume you are the end user of this chiller and not the technician.

So by asking what could have caused one thing or another, are you questioning the competency of the people that carried out the works?
If this is the case your best option is to get it properly surveyed by an independent engineer.

There are multiple reasons which would cause this type of leak, without further hands on examination it will be near impossible to tell what happen. I certainly can't do it from 3000+ miles away, sorry.

Flushing the compressor with Nitrogen and vacuuming it out repeatedly will dry water out of it and will not cause it any harm.
But what inhibitors, antifreeze agents and other chemicals has been added to the water? How clean was the water?
And, again, only a closer inspection will tell if it is worth trying and in the end it will be down to trial and error...

Oh, if you are trying to dry it out, don't forget that all it's oil need to be replaced together with a lot of other components from around the refrigeration circuit.


In The end, I agree with NNN above, but sometimes the best engineering solutions are not available.

:rolleyes:

[goshen]

Hi
when you say plant was stopped.
do you mean due to short circuit?
good luck

[Tesla]

A new chiller would be the least painful path to travel. I once spent 80 hours pulling apart a centrif that filled with water and cleaned up all the parts and flushed the vessels at great cost. In the end due to no one covering warrnety on the work - it was not put back together and the chiller replaced. The cause of the one was fatigued condenser tubes possibly from poor quality tubes. Also the chiller had a history, at only 150 hours running the bearings had to be replace. It was a little less than 5 years old when it filled with water. It blew water through the ruptue valve and most of the dammage was above the water line. The tubes wer tested with eddy current which found more tubes were about to fail.

[Magoo]

Rip it out and start again with a new chiller, the down time, cost of repairs and recovery out weighs the the total replacement costs, reliability if repaired will be low and expensive to maintain.

[yorkman_gr]

All of they above comments there correct, but i will go with Magoo, so i will say to you dont bother to repair and replace the chiller,the repairing costs are huge and your bigest problem is how to get the water out of your system, that it will cost you time , oil, and of course money.
And the next time you try to recover the ***** from a chiller let the bloody pumps runinng, condesnor and evaporator,and that is answering your question b.
Good Luck

[mark957]

I think the problem is due to the discharge of cooling water to the pumps off.
Of course, after the leak repaired or replacing the evaporator, the compressor must be removed and dry, should you get air in the circuit so that you get a deumudificata dehydration up to 90% to follow it to empty, replace the compressor to replace the 'lubricating oil and good luck ....

[balapmurugan]

I am the originator of the thread. Would like to update the status of compressor immersed in water.

Complete overhaul of compressor was done. All bearings were replaced. All O-rings, Seals, Gaskets were changed. Dehydration was done. Affected tubes were plugged. Fresh oil was charged after thorough leak testing of system and triple vacuum (800 microns). Gas was charged and chiller was restored back to operation. 2 Nos of Motor terminals were replaced and motor winding including terminals was found to raise to 50 Meg.Ohm due to continuous heating use space heaters.

My question is a) what is the failure mechanism of the evaporator tube during gas removal. The gas removal job was done through a vendor's subcontractor and it was not sure if the chiller and condensor water lines were kept open for water circulation.
Will the capacity of the pump that was used for evacuvating the gas matter and what is the minimum vacuum level that we could go for while gas removal and what will happen if one continue to remove gas beyond certain vacuum level. What are the general precautions to be handled during the gas removal time from the chiller.

I am new to this HVAC field and would like to gain some info from the experts here.

Thanks

[yorkman_gr]

About your question i think i have answered it on my previous replay, but seem you don't get it in the first place so i will answer you again. When you recovering ***** from a chiller with flooded evaporators, or any chiller, a) you don't leave the recovery running with out some one checking pressures, b) you don't just connect the hoses and you remove the ***** , first you make sure that the first think you recover is the liquid and not the gas, recovering the liquid first speeding up the recovering process,c) IMPORTANT, YOU RUN THE WATERS PUMPS, if you don't run the pumps you take a huge risk to freeze up your evaporator or condenser, and that is what i am thinking happen to your case.If for any reason you are not able to run any pump then the best thing can do is drain the water out of they evaporator or condenser and then you can proceed with the recover of the ***** , and always remember, first the liquid and then the gas.You said that the chiller is running again, did you carrie out acid test in the first our of running?are you sure there is not any moister left in your system? is the pressures and temperatures normal, and i assume the unit is running on 134a with synthetic oil, keep in mind that water can remain in any part of your system and it will return back to your oil so you need to monitor the chiller very carefully and very often just to make sure everything running like suppose to be, i will suggest to you at least carrie out two acid tests a day just to be on the safe side. A good vacuum is 270Pa or 2,7 millibar or 2 Torr. And the next time if you have some troubles just call JCI don't take for grounded that every hvac tech know what is doing.