RTAC Compressor Noise

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Originally Posted by Gear-Drive Guru

If the evaporator is oil logged then the oil mixed with the refrigerant will be at the bottom of the evaporator where the refrigerant is pooled. If the liquid entering the evaporator has that much oil in it then the oil separators are doing nothing or the unit has been overcharged with oil. The oil separator is efficient as the load increases but does not preform well at part load but does still separate. Has oil ever been added to the chiller?

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This chiller has never had oil added to it... Considering the amount of gunk that I have pulled out of the strainer in the oil scavenger line, I am going to check for a clog at both ends of it... I actually have a co-worker coming tomorrow to help me figure this out, he has worked for Trane for 42 years, so I am sure we will get it figured out... I'm a new guy with Trane, only 3 years now so he will once again get me straightened out... His role, considering his tenure, is training now... I appreciate all the input guys and I will definitely post the results of tomorrow's testing...

There is a lot still needed like the evap approach with a unit that is oil logged it will have a high evap approach.Also it is a waste of time to pull the charge just go by superheat. Also the master oil valve is more than likely ok when they fail 90%of the time they shut the unit down on oil flow fast. You can check your acceptable pressure ratio to tell if the oil filter is good but if it was bad the chiller goes off on intermediate oil pressure most of the time.

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Originally Posted by FixItRight

There is a lot still needed like the evap approach with a unit that is oil logged it will have a high evap approach.Also it is a waste of time to pull the charge just go by superheat. Also the master oil valve is more than likely ok when they fail 90%of the time they shut the unit down on oil flow fast. You can check your acceptable pressure ratio to tell if the oil filter is good but if it was bad the chiller goes off on intermediate oil pressure most of the time.

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I meant to say charge by subcooling not superheat.

I've been working on these machines since they first came out over 10 years ago and I've worked on hundreds of them. I stand by what I stated in my previous posts as I've dealt with this exact problem many times. The oil seperators are not 100 % efficient, so if your scavanger line is clogged, your evap will eventually get oil logged and you WILL get liquid carry over. This vintage is the RTAC Plus which has the evaporator with the internal liquid vapor seperator. They are very susceptible of foaming and liquid carry over when they become oil logged. On this vintage, the oil seperator is more efficient at part load. So, if your evaporator is oil logged, you run the circuit fully UNLOADED to return the oil to the seperator after you get the scavanger line cleared out.

Agreed R123.... unfortunately my problem isn't oil related... It's mechanical within the compressor. Evaporator approach is 3 * at 80% load, oil separator level is 7", oil scavenging line is not stopped up, oil pressure is great, oil filter has a good dp. We are going to refer to the service e bulletins to see if this has been addressed yet and go from there... I appreciate the advice you guys have given me...


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Originally Posted by martinfd1975

...oil pressure is great, oil filter has a good dp...

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what is 'great oil pressure'? what number does an oil filter have when it has a 'good dp'?

technical help requires technical numbers. you if need help, you are no longer allowed to make decisions about what is 'good' or 'bad'. you need to post everything. sometimes an 'acceptable' number is actually 'unacceptable' if certain other conditions are present.

do you have glycol (type and percentage) or water? and what is your actual flow rate or actual pressure drop? and what is the design? something is starting to hit me kind of funny about this job.

Actually, as stated above, I had my co-worker (Trane tech for 42 years) at my location Thursday. That is why I made the statements that I did. As far as not having the right to make decisions, even when the senior level techs come to my location, I still make the decisions based on the info they give me. My last post was actually made to say that I wanted to close this discussion.. thank you all for the helpful input.

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Martin, I'm glad you got your problem taken care of. I was actually directing my comments to some other techs who made posts on this thread.