Another Chiller Teardown & Rebuild

[Tech Rob]

I've never seen that bearing bracket removed while the motor is still mounted to the discharge volute. Do you plan to replace the motor-to-volute o-ring? How about the discharge volute-to-condensor o-ring? Appreciate the pics. Very nice equipment room... once you get past the chilled water lines above the starter.

It is a lot easier to do that front bearing bracket with the thrust bearings removed, or at the very least, with the thrust bearing support removed. It is even easier still to do it all with the motor sitting on a cart on the ground.

It is a nice, well lit mechanical room with a lot of clearance and room to work without interference. The guys and gals at this site work very hard to keep everything in good order.

[Freightshaker]

Thanks for sharing looks fun.

[milkyway]

Thanks! My motto is "fake it until you make it"!!!

Lol., cant fake that that too much., good job rob!!
Rob for president ,,

[milkyway]

So do u use a second chain fall for the shaft to pull the bearing off,(I am assuming)
To pull off the seal (journal) I only see one.

[Tech Rob]

Lol., cant fake that that too much., good job rob!!
Rob for president ,,

So do u use a second chain fall for the shaft to pull the bearing off,(I am assuming)
To pull off the seal (journal) I only see one.

Yes. First chain is to lift the shaft enough so you can remove the bearing support. Once you get it out far enough, you put the dial back on the shaft and put a chain behind the bearing support. Transferring the weight of the shaft from one chain to the other is the trickiest part of the whole job.

[AiResearch]

Very cool. Those of us DX guys dont get to see too many of these...disassembled anyway!

Any ideas as to the cause of bearing failure? Oil system blunder?

Thanks for sharing and keep em comin!

[Tech Rob]

Inside the oil tank. Up top is what is commonly called the foam breaker, although that's not really what it does. It's just a mesh screen. On the other side of it a vent line that vents the oil tank to the lowest pressure part of the system. On the back of the tank is the splash guard that covers the oil return from the journal bearing.


Here is what the oil pump and motor looks like with the tank head removed.


Pulled off the oil line to make sure there were no slugs of sealant or other blockages in the internal oil line since there is no other way to get to it once everything is re-assembled.


Here's the gear from the oil pump. The oil pump is a positive displacement gear pump similar to those used in large semi-hermetic reciprocating compressors.


This is the end of the oil pump that is directly coupled to the motor. Oil comes in through the top port and is discharged through the copper line attached to the bottom port.

[Tech Rob]

And here's the view just outside the chiller plant door

[AiResearch]

Hey Rob can you describe the "air run" with the suction elbow off that you mentioned in your other tear down thread? For those of us who dont know.

Im assuming it is not to check rotation.

[Tech Rob]

Sure! An "air run" is when you start the chiller while it is still disassembled to do a balance check and make sure none of the parts interfere with one another once the shaft starts spinning. The process only takes a few minutes. Most chillers have some safeties that need to be defeated before you can do this.

If you replace any part of the rotating assembly like the motor or impellers, you will need to have it balanced. Typically, if you re-use all of these parts, nothing needs to be changed as far as balance is concerned. It still must be checked, though. It's better to find out while it's all still disassembled, than to find out after it's re-assembled, evacuated, and charged.

[AiResearch]

I gotcha. That makes sense.

So you are discharging atmosphere into the condenser? What happens to the motor current during the procedure?

Do you allow it to come up to speed or just bump the starter?

I would assume one wouldnt do this on a McQuay.

That would be scarier than Halloween!

[AiResearch]

And here's the view just outside the chiller plant door

Tampa?

Niiiiiice.

[jnsrose]

Awsome pics. Love the work you do. Especially love the way you talk us through each pic. Thank you for sharing.