ReplyGrey oil full of metal is about as bad as it gets.
I wouldn't even think of running that machine(s) without a complete teardown first.
Professional Member
I am involved in a small frozen food warehouse. The unit is a Tyler has two copeland six cylinder compressors probably about 25 ton. Our companies mechanic that took care of this is no longer with us. The customer lost a compressor. It was vibrating badly and low oil presure. It was replaced about a week ago. I went out on friday on a high temp call. New compressor vibrating badly,low oil pressure.Oil is grey and full of metal. Shut unit down.They have common suction/discharge,an oil seperator,henry oil level control,accumaltor,receiver,three evaporators,R507,oil coolers, timed defrost,
no unloading. The case is controlled by a temperature controller and compressors cycle on pressure switches. It seems as though the previous compressor and the new have the same problem. What superheat and subcool would I normally see on this freezer application. I am thinking possibly an oil return problem. No level in the Henry cannister. The oil safety was not tripped. Pressure on guages only indicated about 4-5 lbs. Any help is appreciated. Thanks
Professional Member
Grey oil full of metal is about as bad as it gets.
I wouldn't even think of running that machine(s) without a complete teardown first.
UA LU189
Professional Member
Get a new pump because you murdered that last one.
Install it.
Replace ALL filters.
Do an oil change.
Pull apart the oil separator and clean that.
PROVE operation of ALL operating and safety controls.
Verify that you have a solid column of liquid to the TXV. Subcooling isn't normally used on equipment like this, a sightglass is.
DO NOT walk away until you KNOW what caused the failure. Yes, that means you will have a long, ball-busting day, but Copeland isn't going to warranty incompetence.
Once you've got all of that done, come on back and tell us what the Superheat is before and after defrost.
Professional Member
Not going to run it. Compressor one week old. Going to have to replace. Just looking for info so we don't loose another.
Professional Member
Continuing my prescription....
Return the following day.
Replace the oil and all filters.
Re-check all of your measurements from the day before.
Return 48 hours later. If the oil has ANY color to it at all, repeat the oil and filter change.
After 48 hours with no color change to the oil, draw a sample and send it to National Refrigerant's laboratory and follow their recommendations from there.
Professional Member*
You got a number of possible suspects on that one bud.
First off, you need to verify that your oil pressure safety switch is actually working, not bypassed.
Second, you need to make sure your Liquid Line Solenoid is fully closing when the temp is satisfied and when in defrost.
Third, you need to make sure your TXVs are not dumping Liquid down the equalizer tubes.
Do these things prior to replacing that compressor again, let us know what you see.
The views and opinions posted here are my own. They do not reflect the corporate policies of my employer and will most likely get me fired at some point.
Professional Member*
Yeah. what he said too.Originally Posted by jpsmith1cm
Get a new pump because you murdered that last one.
Install it.
Replace ALL filters.
Do an oil change.
Pull apart the oil separator and clean that.
PROVE operation of ALL operating and safety controls.
Verify that you have a solid column of liquid to the TXV. Subcooling isn't normally used on equipment like this, a sightglass is.
DO NOT walk away until you KNOW what caused the failure. Yes, that means you will have a long, ball-busting day, but Copeland isn't going to warranty incompetence.
Once you've got all of that done, come on back and tell us what the Superheat is before and after defrost.
The views and opinions posted here are my own. They do not reflect the corporate policies of my employer and will most likely get me fired at some point.
Professional Member
I realize the compressor is done. I am asking about the superheat so, I know I am ok while running. I want to be thorough. I also believe I should check superheat on each of the three evaporators. I am not going to run it,get back on this sight at night, tell the superheat and be wrong. I will not leave it that way.I don't want to be a MURDERER or INCOMPETENT. I just wanted to know what the superheat should be in this application.. The seperator can not be taken apart. I am suspecting an issue with the oil level control/cannister and oil safety not tripping. This is because the seperator has common oil return line to both compressors. The other compressor oil level is ok. Common suction/discharge lines also. I have not performed any diagnosis at this time. Call late friday and shut the compressor down. I always check oil safety on any new compressor intalled. All other safeties are also checked.
Professional Member
Copeland says no more that 20 degrees SH at the compressor.
Professional Member*
Gotta say, sounds to me like you got a floodback problem. Copelands like 20 or so deg S/H at the suction endbell.
The views and opinions posted here are my own. They do not reflect the corporate policies of my employer and will most likely get me fired at some point.
Professional Member
The solenoid does shut off. The defrost timer did shut off solenoid valve and pump down while I had just began checking the recent install. The compressor that had been changed, has been down for about a month.The other one has been maintaining the case at 5-6 deg.. From reports I read ,it seems to be the same failure issue.
Professional Member*
Check your TXVs. The equalizer tubes should not be dumping liquid.
The views and opinions posted here are my own. They do not reflect the corporate policies of my employer and will most likely get me fired at some point.
Professional Member
Ok, maybe I came off a little strong.
It pisses me off when guys toss a new compressor in a unit and NEVER think about what killed it.
These questions should have been asked when the first compressor was replaced, not after the second one died.
Not to further offend, but what method did you use to test the safeties?
It is not enough just to push the button and see the compressor drop off.
Professional Member
I will replace the filters. Check safeties. Replace the henry oil level cannister. Replace compressor .Check superheat on each coil and at the compressors. I guess I will have to babysit the old thing a couple days. Thanks
Professional Member*
In a freezer, you should be looking at like 6 deg S/H leaving your evaps.
The views and opinions posted here are my own. They do not reflect the corporate policies of my employer and will most likely get me fired at some point.
Professional Member
It may not be necessary to completely replace the oil separator.
You will have to see what type it is (helical or conventional). Helicals don't need to be replaced as there really isn't anything that can go wrong with the separation mechanism. There IS, however, a float in the bottom of it that is probably plugged up.
Professional Member
At compressor start up I always engage the new contactors, when wiring not connected to the compressor. I allow the oil safety to time out. To confirm operation. I appreciate the help. I just have not worked much with the low temp and R507. Thanks
Professional Member*
It could be a wet suction issue, he said there was an accumulator..
Is it large enough for two 6 cyl semi's?
Im thinking lubrication prob from oil float or associated component or line.
He didnt say how nice or clean the condensing unit is, many times, if it caked in oil and grease on the outside, there is sludge and varnish and carbon and sticky parts on the inside.
Professional Member*
I dont think he is replacing the oil separator, just the oil level control on the compressor.
Professional Member
The cannister I am talking about is on the side of each compressor. It has a sight glass and an adjustment to control the oil level. It mounts on the compressor where there is normally a sight glass. The seperator feeds both of the Henry cannister/level controls. There is no oil equalizer line as would be normal in an a/c application. I may not be using the correct terminology for this cannister/level control.
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