Two YTJ-67 Compressors
I have two YT chillers used with R-11 refrigerant,
they were initially started up twenty six years ago,
for the past 7 years, they have been left unused, and now the customer wants to reuse them for their supermarket air conditioning,
I just had the compressors(YTJ-67) disassembled,
both compressors' bearings and seals(Balance piston and eye seals) have some scrtches and scuff marks on the inner surface, and on the outward surface, there seem to be corrosions that I suspect it was caused by moistures in the refrigerant system and no lubrication(as I mentioned these two chillers have been put idle for 7years),
My questions are:
1. are these bearings still useable?
2. what is the life span for Aluminum Alloy bearings used in York centrifugal compressor?
Any advice will be much appreciated.
Some more pictures of chiller A,
As to the PRV control shaft lubrication issue,
the lubricant used is described as Beacon Grease and Molykote with P/N 360-00125 in the service manual as attached,
because I did not order the lubricant from York,
I consulted with the engineer of Molykote dealer in my city, and he suggested me to use Dow Corning 111,
can anybody advise if it is feasible?
Thanks in advance.
who cares if they are still usable? it is already open, replace them especially if they are questionable.
Someday, I hope to be just as brave as Harry Stamper.
clean them up and mic them and see if they are in specs.
Originally Posted by freonrick
could you provide the detailed information of the test for aluminum bearings?
thanks in advance.
Hard to tell the condition from a picture in this case.
Did you ever figure out why that YK was losing oil and then getting it back at shutdown?
1. I think as stated earlier what are the spec readings ?
2. Is the customer ok with using these parts if so failure could happen sooner than later ?
3. If it was your machine what would you do ?
4. Aluminum bearings should last for quite some time if properly lubricated and not exposed to atmospheric conditions for any lenght of time.
5. What does the rest of the machine look like ?
6. Clean up kit if you do decide to reassemble should be installed.
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For these two compressors, we only picked up the one with better condition to repair, we have order new bearing kit, gasket kit, shaft seal, eye seal ring and B.P seal ring for replacement,
We also sent the impeller locked with high speed shaft to a factory for dynamic balance emendation, what they do, they put the impeller with H.S shaft on a test machine(Schenck, made in Germany), accelerate to at most 1800RPM, and they adopt weight-removing method to achieve acceptable balance,
This is somewhat controversial to me, firstly the speed for test is far less than the real speed, I doubt the result wont be able to reflect real condition, secondly, when every time they grind away some weight from my impeller, I am a little fearful, I am afraid that too much weight could be taken off,
Just wonder what you do the balance for impeller in USA,
The compressor has been assembled already, I havent thought of the roundness of the shafts as their surface looked smooth, if it is imperative, then I think it is better for me to disassemble the compressor for further roundness examination.
Gentlemen, thanks for your advice, I do have learned a lot from you.
Thanks for your reply,
I apologize for my short of knowledge of Aluminum material,
can anybody here kindly inform me more about the spectrum?
what is the test and what fact can it clarify?
actually I have suggested my customer to replace all the bearings as none of us dare to take risk of possible failure,
because the price of two sets of bearings is as high as about $65,000,
and my customer don't have any extra budget for the expense this account year,
so they incline to reuse those bearings if they are still usable or can last for at least six months,
when I opened these two compressors, they looked terrible,
rust and dirt are everywhere inside the machine,
it has took me one week to clean them and the job is still ongoing now,
if the spectrum can clarufy the condition of bearings, then I would think of doing it first.
again, thanks for your opinions to this matter.
This is getting way too detailed for an open forum.
Agreed. I should have never said those things. MODERATOR: Can you delete my post #9? Taicool, you need to apply for Pro Status. Technical discussions need to happen there, not out here in public.
I think a chiller tech needs to be involved hands on so they can see the whole thing. something can be misinterpreted when we cant see what you have as a whole. too much money involved for a mistake.