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  1. #1
    Join Date
    Feb 2010
    Location
    UK
    Posts
    13

    turbocor not loading

    Hello from the UK,
    I have came across a problem on two turbocor compressors, TT300 where the IGV does not open and therefore the compressors do not load.
    I have followed the troubleshooting guide, and this would indicate a serial driver fault as all backplane voltages are correct etc. The leds for Igv do not flicker when a command for IGV open or close.
    However, on power up the backplane leds for cool solenoids and the run led light, also the alarm led starts and stays green. The compressor still appears to go through a precheck and does not alarm and is still capable of operation, monitor programme still ok.
    A third compressor on site operates ok, and on power up the alarm led lights red, precheck takes place and then alarm reverts to green and igv motors shut with igv leds flickering.
    I have swapped serial cards and found that the fault remains the same and that the working compressor still works as before, therefore not the serial driver at fault.
    Has anyone any ideas?
    Your advice would be greatly appreciated.

    Phil

  2. #2
    Join Date
    Aug 2003
    Location
    Fort Worth, TX
    Posts
    11,317
    Don't know much about Turbocors (would love to have one at my plant) but I'm sitting here wondering what actually drives the guide vanes? I would think some kind of motor...is it getting power? Is there feedback between the guide vane position and the controls (like a potentiometer)?
    • Electricity makes refrigeration happen.
    • Refrigeration makes the HVAC psychrometric process happen.
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  3. #3
    Join Date
    Feb 2010
    Location
    UK
    Posts
    13
    Thanks for the reply shophound,
    the igv is driven by a stepper motor, 15vdc. There isnt any power to the stepper motor, the serial driver should take care of that. It would appear that the the control doesnt really know where the vanes are at as I am trying to drive them manually to 110%, the monitor shows them opening as a percentage but the actual indicator still shows closed.
    Under normal conditions the vanes are driven shut at the end of every cycle and also on every power up.

    Phil

  4. #4
    Join Date
    Aug 2003
    Location
    Fort Worth, TX
    Posts
    11,317
    How do the vanes feed back to the controller what their position is?
    • Electricity makes refrigeration happen.
    • Refrigeration makes the HVAC psychrometric process happen.
    • HVAC pyschrometrics is what makes indoor human comfort happen...IF the ducts AND the building envelope cooperate.


    A building is NOT beautiful unless it is also comfortable.

  5. #5
    Join Date
    Feb 2010
    Location
    UK
    Posts
    13
    Quote Originally Posted by shophound View Post
    How do the vanes feed back to the controller what their position is?
    To be honest I dont know. I assumed it would be some clever electronics ( or even some simple ones), but I am wondering whether it is just a case of stroke time for full travel, as on each power up the vanes are driven shut for a period regardless of their present position.

    Phil

  6. #6
    Join Date
    Mar 2003
    Posts
    7,321
    are you actually getting the voltage ot the stepper motor/ have you verified? do you have a signal generator? if you are not getting it to drive, you could try manually loading it with a signal generator to see if its the motor.

  7. #7
    Join Date
    Feb 2010
    Location
    UK
    Posts
    13
    Quote Originally Posted by flange View Post
    are you actually getting the voltage ot the stepper motor/ have you verified? do you have a signal generator? if you are not getting it to drive, you could try manually loading it with a signal generator to see if its the motor.
    Thanks for the reply,
    No, there is no voltage at the stepper motor, the problem appears to be in the electronics on the backplane or a software problem. The led's on the backplane are indicating completely different than another correctly operating compressor although no alarm is flagged.
    I am on my way back to site now to investigate further.

    Phil

  8. #8
    Join Date
    Feb 2010
    Location
    UK
    Posts
    13
    i spent some time looking in to the problem again, confirmed backplane voltages etc. I disconnected everything on the backplane and removed the backplane assembly for a closer inspection. Nothing obvious.
    Fitted everything again checking all connections good.
    Powered up and found still the same. The fault is replicated on another compressor as well.
    Chiller oem will provide replacement bmcc and serial boards soon as well as an igv motor assembly etc.
    So I am now waiting for parts and a return to site soon.
    If anyone has any ideas in the meantime please!!

    Phil

  9. #9
    Join Date
    Mar 2003
    Posts
    7,321
    if the only issue you have is chiller loading, and everything else is fine, I would get me a big old lawn chair and some cabling. sit there and control the vanes with a signal generator in one hand, and my laptop in the other so i could watch the compressor. Wait, laptop not in my hand, you will also need a folding table on which you can rest the laptop. good thing it isnt august.

  10. #10
    What is your chillers brand and model number.If it is a Mcquay,what version of software
    does it have,do you have the software to connect to the compressor?What service book
    are you using?

  11. #11
    Join Date
    Feb 2010
    Location
    UK
    Posts
    13
    Quote Originally Posted by allchlrstech View Post
    What is your chillers brand and model number.If it is a Mcquay,what version of software
    does it have,do you have the software to connect to the compressor?What service book
    are you using?
    Hi Allchlrstech, the chiller is an Italian brand not McQuay, the bmc software rev is 2.02685, cc software rev is 1.3.917 and parameter rev 18 all dated march 07.
    The service manual I am using is ECD-00007-s-r03v02. December 2007
    I have the turbocor monitoring tool vers 2.10.80
    I disconnected the cable for the i/o board so that there are no external influence except for 400v 3 phase supply(european spec) and found that the led sequence on the backplane remains the same.
    We have also put out an enquiry to turbocor via OEM.
    I am now away from this site but have another two turbocors to look at today that start correctly and load etc so I can make some further comparison. I am not sure when I will be able to get back to site, thats up to the boss.

    Phil
    Last edited by ptsac; 05-27-2010 at 05:53 AM. Reason: more info

  12. #12
    Join Date
    May 2001
    Location
    Western Wa
    Posts
    1,831
    Is the compressor in "choke" mode due to insufficient delta P between cooler and condenser?
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  13. #13
    Join Date
    Feb 2010
    Location
    UK
    Posts
    13
    Quote Originally Posted by Randy S. View Post
    Is the compressor in "choke" mode due to insufficient delta P between cooler and condenser?
    The igv is not being driven as there is no drive command. The compressor ramps up to say 24000 rpm and I suppose just protects itself as the vanes do not open,there is no drive supply to the vane motor.
    However the problem appears to be evident from power up. The pre and self check sequence differs from a non problem compressor with relation to the leds D7 COOL-H, D10 COOL-L,D11 RUN & D12 ALARM. I have compared another 2 compressors on a different site today and the sequence on power up is as the only working compressor on the subject site.
    I am leaning towards the bmcc as being the culprit, but I will have to wait for the oem to ship.

    Thanks for all your input, I shall keep you posted as to the outcome.

    Phil

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