Results 1 to 28 of 28
  1. #1
    Join Date
    Jan 2006
    Location
    Canada
    Posts
    32
    Rep Power
    0

    High Deferential Oil Pressure Alarm



    We have FES Ammonia compressor 200 HP, once a while we get "High Deferential Oil Pressure Alarm" and "Low Suction Pressure Alarm" together, the compressor stops for these alarms. We reset then works for a while may be few days. that happened two years ago then gone. Now again last week one time, and this week one time.

    I appreciate if any can help for the reason?



  2. #2
    Join Date
    Jan 2006
    Location
    Croatia
    Age
    68
    Posts
    2,299
    Rep Power
    31

    Re: High Deferential Oil Pressure Alarm

    Hi, NNNNNN

    Quote Originally Posted by NNNNNN View Post
    We have FES Ammonia compressor 200 HP, once a while we get "High Deferential Oil Pressure Alarm" and "Low Suction Pressure Alarm" together, the compressor stops for these alarms. We reset then works for a while may be few days. that happened two years ago then gone. Now again last week one time, and this week one time.

    I appreciate if any can help for the reason?
    For the first one could be a clogged oil filter

    for second one: maybe clogged suction filter on compressor, obstruction in refrigerant delivery to evaporators, too small or no load...

    Tell us something more about your system, please.

    Best regards, Josip

    It's impossible to make anything foolproof because fools are so ingenious...

    Don't ever underestimate the power of stupid people when they are in large groups.

    Please, don't teach me how to be stupid....
    No job is as important as to jeopardize the safety of you or those that you work with.

  3. #3
    Join Date
    Mar 2006
    Location
    Merate (LC) - Italy
    Age
    52
    Posts
    2,554
    Rep Power
    24

    Re: High Deferential Oil Pressure Alarm

    How cold is these days?
    Is it colder or warmer than last year?
    How does it compare with two years ago?

  4. #4
    Join Date
    Aug 2005
    Location
    USA
    Posts
    5,326
    Rep Power
    25

    Re: High Deferential Oil Pressure Alarm

    Low suction pressure and high differential oil pressure sounds like a cold start.

    Cool oil injection temperatures will cause the high differential pressure, and if the ambient is also cool enough to where you canot deliver liquid to the evaporators, the suction pressure will decrease.
    If all else fails, ask for help.


  5. #5
    Join Date
    Jan 2006
    Location
    Canada
    Posts
    32
    Rep Power
    0

    Re: High Deferential Oil Pressure Alarm

    After the first time last week, we thought it was the filter, replaced it. We are going to change the oil.

    Out side temperatures those days 0 Deg C +-

  6. #6
    Join Date
    Jul 2006
    Location
    USA
    Age
    73
    Posts
    867
    Rep Power
    26

    Re: High Deferential Oil Pressure Alarm

    Am assuming you have a Micro II or III 3E panel. If this is correct, check the calibration of the sensors first. Very simple procedure, which is in the Panel Manual.

  7. #7
    Join Date
    Mar 2006
    Location
    Merate (LC) - Italy
    Age
    52
    Posts
    2,554
    Rep Power
    24

    Re: High Deferential Oil Pressure Alarm

    Quote Originally Posted by NNNNNN View Post
    After the first time last week, we thought it was the filter, replaced it. We are going to change the oil.

    Out side temperatures those days 0 Deg C +-

    I don't think the oil has anything to do with it.
    I think it's a low ambient temperature causing too much subcooling and results in low suction pressure.
    Either you've got too much refrigerant or there's no condensing control in the unit.

  8. #8
    Join Date
    Jul 2006
    Location
    USA
    Age
    73
    Posts
    867
    Rep Power
    26

    Re: High Deferential Oil Pressure Alarm

    Just looked at my previous post.
    I left a couple of things out.
    In addition to checking the calibration of the pressure and temperature sensors, as well as the calibration of the slide valve, check to be sure that the machine unloads properly. I am assuming that the correct set points are entered in your panel.
    On occasion the older panels will become erratic. This is often caused by a power supply problem, which can be replaced.
    Unless the panel has a problem, the two failures are probably not related.

  9. #9
    Join Date
    Aug 2005
    Location
    USA
    Posts
    5,326
    Rep Power
    25

    Re: High Deferential Oil Pressure Alarm

    What is the oil sump temperature on the initial start-up?

    Changing the oil does not seem right and I would not expect any appreciable difference by doing so.
    If all else fails, ask for help.


  10. #10
    Join Date
    Jul 2006
    Location
    USA
    Age
    73
    Posts
    867
    Rep Power
    26

    Re: High Deferential Oil Pressure Alarm

    Quote Originally Posted by US Iceman View Post
    Changing the oil does not seem right and I would not expect any appreciable difference by doing so.
    Correct.
    If the oil were in a condition it is causing this problem you would be in big trouble indeed. Most likely shipping the Screw off to FES for an overhaul!

  11. #11
    Join Date
    Jan 2006
    Location
    Canada
    Posts
    32
    Rep Power
    0

    Re: High Deferential Oil Pressure Alarm

    We have changed the oil today, every thing as before.

    Oil Sep. temp. starts at 113.7 F after five min. go up to 120 F or 121 F.

    Starting Oil Diff. Press. is 94.4 psi and after 5 min. reaches to 112.6 psi

    Delta P for the oil pump is about 15 psi

  12. #12
    Join Date
    Jul 2006
    Location
    USA
    Age
    73
    Posts
    867
    Rep Power
    26

    Re: High Deferential Oil Pressure Alarm

    Did you check the Sensors?
    You can verify the readings with the Gage ports under the panel. (You have not confirmed if it is a Micro Panel, so I am assuming.)
    You can connect ports to these with a ***** hose connected to a Gage TEMPORARILY. Do not use a manifold. NH3 is hard on the brass.
    Something is wrong if your oil pump is putting out 15 PSI and you are showing 100PSI differential. The figures do not add up.

  13. #13
    Join Date
    Jan 2006
    Location
    Canada
    Posts
    32
    Rep Power
    0

    Re: High Deferential Oil Pressure Alarm

    - Yes the panel is Micro III
    - The defferential Pressure for the Pump is 15 psi (out-in)

    - I will be getting ports reading and inform you

    -Regarding calibration of the sensors (Kindly I would ask you about the sensors you are mentioning? which sensors?)

    Thanks.

  14. #14
    Join Date
    Jul 2006
    Location
    USA
    Age
    73
    Posts
    867
    Rep Power
    26

    Re: High Deferential Oil Pressure Alarm

    Quote Originally Posted by NNNNNN View Post
    - -Regarding calibration of the sensors (Kindly I would ask you about the sensors you are mentioning? which sensors?)Thanks.
    The pressure sensors are located under the panel by the gage ports. They each have a cable that runs up into the panel to the terminal strip at the bottom of the main board. They are labeled as to their function.
    Connect a gage to the ports one at a time and compare your readings to the panel readings.
    The recalibration procedure is in the manual. Very easy to do.
    I am concerned about the low pressure differential you are reading across the pump. This is quite low.
    A quick test of the sensors is too shut off the machine. All pressure readings should be the same except the suction. (It is measured upstream of the suction check)
    Another possibility is an erratic sensor, or the wrong type installed. The board can be adjusted via jumpers for voltage or Milliamp sensors.
    Jan Clark at FES in York, Pennsylvania can assist you if you have questions regarding sensor types. Or you most likely have a Rep in your area.

  15. #15
    Join Date
    Jan 2006
    Location
    Canada
    Posts
    32
    Rep Power
    0

    Re: High Deferential Oil Pressure Alarm

    Hi NH3LVR,

    We have checked the calibration. only 1/2 to 1 psi diff.
    it seems OK

    Readings are:

    1- When the compressor is OFF:
    Suction Pressure: 20.0 psi
    Discharge pressure: 107.2 psi
    Inlet Oil Pressure: 107.3 psi
    Oil Filter Inlet Pressure: 106.8 psi

    2- When Sterted to run (after three min.)
    Suction Pressure: 20.1 psi
    Discharge pressure: 132.2 psi
    Inlet Oil Pressure: 126.2 psi
    Oil Filter Inlet Pressure: 135.0 psi

    3- When Sterted to run (after ten min.)
    Suction Pressure: 18.8 psi
    Discharge pressure: 116.0 psi
    Inlet Oil Pressure: 126.2 psi
    Oil Filter Inlet Pressure: 125.0 psi


    Note: The Filter Diff. pressure was around 8.9 psi
    The Filter, Strainer and Oil has been changed one week ago.

    Oil diff. pressure. 98.2 psi

    Thanks
    Last edited by NNNNNN; 29-03-2007 at 10:58 PM.

  16. #16
    Join Date
    Jul 2006
    Location
    USA
    Age
    73
    Posts
    867
    Rep Power
    26

    Re: High Deferential Oil Pressure Alarm

    I am a bit confused here.
    Not know your particular machine makes this a difficult problem. Although i work on FES machines (Mostly older) regularly I have not seen them all.
    I am on the road at the moment, so have had little time to look at this.
    Does your machine have a large Viking oil pump (10-15 HP) Is it set up to run full time? It appears you have almost no oil pressure.
    Is this a older machine with the micro 3 added? If so I would look at the installation and verify the connection and setup.
    I am willing to take a closer look at this when I get home, but as I suggested earlier calling FES might be your fastest solution.

  17. #17
    Join Date
    Jan 2006
    Location
    Canada
    Posts
    32
    Rep Power
    0

    Re: High Deferential Oil Pressure Alarm

    I am not sure regarding the HP will get you that when go to work Tuesday.
    The FES is about 7 years old, got it new at that time. has 24800 hrs. two days ago I have called a person workes on Viking pumps, he opend it found every thing OK with the pump (No wear and clearance is OK).
    I looked today again the compare between the ports and reading on panel (Comp. OFF) all the same different about 2 psi (I don't think that is a big issue).

    Thanks

  18. #18
    Join Date
    Jul 2006
    Location
    USA
    Age
    73
    Posts
    867
    Rep Power
    26

    Re: High Deferential Oil Pressure Alarm

    A break at last!
    In my experience with Micro3's they have always shown the oil pressure as net (35 to 45 lbs over discharge). You are showing gage pressure instead. Dip Switch 6 #3 can change the readings in some cases. It should be in the open position. Closed is service mode to run the oil pump without starting the compressor.
    Software may vary, however, so you should not rely on my experience exclusively.
    Be cautious about the Viking pump. Even if an inspection shows no problem,they still may not pump warm oil.
    A while back I sent two in for repair to a reputable company. They could find no problem. But they needed to be rebuilt before they would function.

    By the way, does anyone have a sure cure for a Mycom screw that does not unload when running, yet unloads when started? The machine unloads, starts, loads up and stays at 100% from then on.
    Electrical seem normal, valve clicks, etc, but it stays at 100%. The unloading valve does not have manual operating stems. I have had this trouble before and ended up rebuilding the entire unloading system.

  19. #19
    Join Date
    Mar 2006
    Location
    Merate (LC) - Italy
    Age
    52
    Posts
    2,554
    Rep Power
    24

    Re: High Deferential Oil Pressure Alarm

    Loading solenoid valve leaking?. Infact only unloads when oil pressure is nil? Just my 0.02 for a thought.

  20. #20
    Join Date
    Jan 2006
    Location
    Canada
    Posts
    32
    Rep Power
    0

    Re: High Deferential Oil Pressure Alarm

    The oil pump motor is BALDOR 3 HP 3.4 A 3ph 1750 rpm
    pump S/N 10996327 PN 290-002330-022
    The pressures that we have got through IN and OUt gauges.

  21. #21
    Join Date
    Jan 2006
    Location
    Valrico, Florida
    Posts
    517
    Rep Power
    19

    Re: High Deferential Oil Pressure Alarm

    Just secound guessing here, but had someone changed a transducer lately and maybe installed the wrong one?

    Does the Mycom have an external oil pump?
    Last edited by nh3wizard; 03-04-2007 at 09:24 PM.

  22. #22
    Join Date
    Jul 2006
    Location
    USA
    Age
    73
    Posts
    867
    Rep Power
    26

    Re: High Deferential Oil Pressure Alarm

    NH3 Wizard:
    Good point about the sensors. Danfoss did have a bad run a while ago.
    As to the FES NNNNNN;
    I am still confused about your machine. FES has used many manufacturer's compressors over the years. (Coby, Mycom, Dunham Bush,and now ELZE. I have never seen one with that small a pump. Not to say that they do not exist, I just have not seen one.
    Fricks use a part time oil pump on some machines. The oil pump is used stickily to unload and prelube before starting.
    Does your oil pump run all the time?
    I am failing to see how this translates to a High Differential Shut down.
    Take some pictures of your machine and post them.

  23. #23
    Join Date
    Jan 2006
    Location
    Canada
    Posts
    32
    Rep Power
    0

    Re: High Deferential Oil Pressure Alarm

    No the oil pump does not run all the time.
    Attached are some picture of our FES comp.
    Attached Images Attached Images

  24. #24
    Join Date
    Jan 2006
    Location
    Canada
    Posts
    32
    Rep Power
    0

    Re: High Deferential Oil Pressure Alarm

    Attached some more picture
    Attached Images Attached Images
    Last edited by NNNNNN; 12-04-2007 at 04:29 AM.

  25. #25
    Join Date
    Jul 2006
    Location
    USA
    Age
    73
    Posts
    867
    Rep Power
    26

    Re: High Deferential Oil Pressure Alarm

    OK, I have to admit I am totally unfamiliar with the Compressor in the picture.
    You apparently have a part time oil pump, used to prelube and unload the compressor before starting.
    I do not recognize the Compressor you have on your package. It seems to have a extra section I am not familiar with.
    What is the setting you have for Oil Differential shutdown? Is there a pre-shutdown alarm setting?

  26. #26
    Join Date
    Jan 2006
    Location
    Canada
    Posts
    32
    Rep Power
    0

    Re: High Deferential Oil Pressure Alarm

    Here are some more photos
    Attached Images Attached Images

  27. #27
    Join Date
    Jun 2007
    Location
    maryland
    Age
    62
    Posts
    5
    Rep Power
    0

    Re: High Deferential Oil Pressure Alarm

    load valve leaking. the o rings start to wear anf this will cause it not to load or unload. the oil is being bypassed in the load unloas cylinder.

  28. #28
    Join Date
    Jun 2001
    Location
    N.Ireland
    Age
    50
    Posts
    1,632
    Rep Power
    24

    Re: High Deferential Oil Pressure Alarm

    Quote Originally Posted by NNNNNN View Post
    We have FES Ammonia compressor 200 HP, once a while we get "High Deferential Oil Pressure Alarm" and "Low Suction Pressure Alarm" together, the compressor stops for these alarms. We reset then works for a while may be few days. that happened two years ago then gone. Now again last week one time, and this week one time.

    I appreciate if any can help for the reason?
    Hi NNNNNN

    I would expect the problem to be on the electrics or the electronics side. Most transducers show low say -50 deg c when they go open circuit.
    I would check the connections and then think about a new transducer or input card.

    Kind Regards Andy
    If you can't fix it leave it that no one else will:rolleyes:

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •