Two YTJ-67 Compressors

[beenthere]

I have no way to access the professional forum because I don't have any american official certificates
Tung

Being from the USA or having certs from it is not a requirement to be a Pro member. Apply and the membership committee will see if they can verify that you are in the HVAC trade.

[Taicool]

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.

[klove]

Use Dow-Corning High Vacuum Grease.

[ga1279]

Taicool - What you are basically looking at is the finesse part of our job. You examine all the bearings for wear indications, metal scraping (wiping), overheated spots on rubbing surfaces. If the machine hasn't run for 7 years you have other problems. The low-speed and high-speed shaft have not been rotated and the weight of the shafts may have settled into the lower portion of the bearing causing it to become an oval and out of round. Depending on the shaft size, you need an outside micrometer to measure the actual shaft diameter, at least 3 sets of readings on each surface the bearing rides on. You are verifying the shaft is 100% round and within tolerance. Next use a set of inside micrometers to measure the inside diameter of the bore of the bearings. In this case the more readings you take the better, just make sure all readings are taken at the same depth as previous readings (ie-1" inside on both sides) 360 degrees and the micrometer stem is perpendicular to the bearing surface. I would also advise an oversized clean up kit as you can't clean the rust from the inside surface of the evaporator or condenser. Good luck and if by chance I'm talking over your head with these directions get a chiller technicians who's been down this street before. No disrespect intended toward you. It just a lot of money involved with this work. -GEO

[sargent york]

photo.jpg Here is a York OT with aluminum bearings apoximatly 30 years old, that has never been overhauled! It was a R11 machine, shells rusted out and tubes had to replaced so we put her out to pasture. She was got a lot of TLC and they got their moneys worth out of her! Bearings? Oil is the bearings, keep it clean, right temp, right pressure who knows high long this one would have run!

[Taicool]

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 won’t 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 haven’t 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.