Trane CVHE Noisy

[mtange]

I'v got a TRANE CVHE320, 5 years old, all of the sudden very noisy. Oil is clear, unit starts OK, unit cools OK, but noise is unbearable. Does anyone have any ideas or suggenstions, am I looking ar a full tear down, rear bearing? Any input is welcome, thanks.

[absrbrtek]

Most likely a tail bearing. Is the noise comming off the back of the motor?

[chillrdude]

Is it a high pitched squealing noise from the rear bearing? Usually copper plating on the rear bearing is the cause, any chance the noise has been there before and has just gotten loud enough to notice.

[lightyear]

Does anyone know weather this is a common problem with this chiller? Tear down every 5 or so years could become expensive for the customer?

[absrbrtek]

They have had tail bearing problems for a few yrs now. We put in 3 800 tonners and all 3 had bearing failures within the first year. Trane has a retrofit where they put a brush on the tail bearing to stop the emf generated by the motor from going through the bearing and pitting the races and balls. They are in denial that they have a problem and are a fix on fail retrofit. They just hope theyll make it thru the 1st yr warranty and then its on the end user. Sad way to do bussiness.

Originally posted by lightyear
Does anyone know weather this is a common problem with this chiller? Tear down every 5 or so years could become expensive for the customer?

[no8no3]

Originally posted by absrbrtek
They have had tail bearing problems for a few yrs now. We put in 3 800 tonners and all 3 had bearing failures within the first year. Trane has a retrofit where they put a brush on the tail bearing to stop the emf generated by the motor from going through the bearing and pitting the races and balls. They are in denial that they have a problem and are a fix on fail retrofit. They just hope theyll make it thru the 1st yr warranty and then its on the end user. Sad way to do bussiness.

Originally posted by lightyear
Does anyone know weather this is a common problem with this chiller? Tear down every 5 or so years could become expensive for the customer?

Abs... have you actually done one of these retrofits? And if so, how did it turn out? So far we have changed nothing but tail bearings, and the brush thing hasn't been mentioned.

[absrbrtek]

Well they feel their the only ones capable of performing it as usual, so their pretty much keeping it in house as usual. I have the bullitan on it that they claim doesnt exist as usual. I personaly havent done one but it doesnt look difficult. Problem is last time I checked they wont sell it to contractors as usual.

There is also a confidental service bullitan out that I have on the pitting of the bearings and races on the VFD 2 and 3 stage machines. They say it is on certain VFD models only but the problem is with all of them including non VFD as far as I can tell.

Its pretty funny, on the 3 VFD units we put in I was there for startup. Units only had nitro holding charges in them. I asked the rep if they were putting the brush kits on? His response was you dont know about that and their not needed. Needless to say All 3 failed in under 6 months. So instead of spending a few hours retrofitting them before startup they had to pull the charges, replace the bearings, retrofit with the brushes, evac and recharge. The retro fit is a fix on fail so they wont due it until the tail bearing craps out.

[Edited by absrbrtek on 10-19-2004 at 11:28 PM]

[no8no3]

I had heard a rumor that they were doing this, but did not know if it was true. It's a shame to wait to do this upon the crapping out of the tail bearing, I know my customers will be soured on this deal and might revert back to buying Mcquay stuff again. I've got two waiting on tail bearings now, and another due for vibration analysis, It's most likely discolored and plated too. Gonna be a long winter.

[lord of the screws]

I started 5 CVHE-F this year out of those 5,3 were VFD machines on return trips one was noisy after 800 hours the other after about 1500 hours the third machine has over 3000 hours on it and has no signs of noise and is running fine also the water cooled drives the first version seems to have alot less bearing related failures than the new rockwell 2.0 refrig. cooled drives.

[dmedley]

Be very careful. Any chiller can wear out any bearings no matter what due to running the chiller in low load conditions on a regular basis.Running any chiller unloaded plays an effect on the miscibility of the oil to refrigerant.If the chiller is running unloaded for prolonged
periods of time the lubrication properties of the oil will decrease on any make or model of chiller.Go back to basic science, the lower the suction pressure the more refrigerant that you can remove from the oil keeping the lubrication properties at its highest level. Question is where is the noise coming from? Is it a low grumble that would pronounce bearing problems. a simple test to prove this is a vibration analysis which could tell what is causing the noise and what it entails.Is the noise coming from the refrigerant velocity running through the impellers due to the guideveins being closed. Refer back to your basic science to see how the refrigerant reacts in the system at different pressures and perform a vibration analysis which is inexpensive compared to a complete tear down to see if there is any thing there to tear down for.

[mdp]

There have been numerous papers written concerning VFDs and bearing failures, all dealing with an electrical current being generated in the armature and using the bearings as a path to ground. Personally I've seen the after effects, kind of interesting that Trane would think that thier machines wouldn't have any problem with this.

[absrbrtek]

Its a problem with the VFD and non VFD models. Put an amprobe around the oil drain on the thrust bearing. Youll get an amp draw. I have their bullitan on VFD induced bearing failures. It makes no mention of non VFD models but the problem still exists.

They are grounding the rotor now on a fix on fail basis. Its a shame they just dont due this at the factory. They feel its not on every model just certain configurations. I kinda disagree but thats JMHO.

Originally posted by mdp
There have been numerous papers written concerning VFDs and bearing failures, all dealing with an electrical current being generated in the armature and using the bearings as a path to ground. Personally I've seen the after effects, kind of interesting that Trane would think that thier machines wouldn't have any problem with this.

[h2045]

ABS, Can the tail rollers be changed w/o going in from the front?Suction Elbow, Vane, Seal, Impeller,Vane,Seal, Impeller,Vane,Seal,Impeller,pull the rotor.
John