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Thread: yt help

  1. #1
    Join Date
    Mar 2004
    Location
    eastern north carolina
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    80

    yt help

    1990 yt,250 tons, runs good during the day, normal shutdown, all pumps stop, oil temp during shutdown is aroung 160 deg., at morning start it runs about one min. & shuts down on low oil press. you can hear the oil pump cavatating.
    high & low oil press sensors are new, after coast down the restart is normal, no oil press flucuation at all & it runs
    good all day, next morning, samething. can anyone please help?

  2. #2
    Join Date
    Jan 2011
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    1,164
    Oil temperature at 160*F is high. What oil temperature are you maintaining in the sump during shutdown? What you are experiencing is what we used to call system depression. There are a couple of things you can do to avoid it. If you open your valves and let the water circulate for about 10 minutes prior to starting the chiller that should help. Does this chiller have an equalizing line solenoid valve?

    The reason you are foaming your oil and cavitating the oil pump is because the equalizing line is rapidly dropping the pressure in the lower sump. Getting the PRV open more quickly can also help.

  3. #3
    Join Date
    Mar 2004
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    eastern north carolina
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    80
    the shutdown is 160 deg, running temp is 125 deg.the foaming starts when the vanes start opening, the vent line solenoid has been replaced

  4. #4
    Join Date
    Dec 2010
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    Down by the river
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    Solenoid has been replaced, but is it being powered and working. Had similar issue that the relay was bad.

  5. #5
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    Dec 2008
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    Dixiana, AL
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    What's your oil level at startup?

  6. #6
    Join Date
    Jan 2011
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    Quote Originally Posted by turbovac
    the shutdown is 160 deg, running temp is 125 deg.the foaming starts when the vanes start opening, the vent line solenoid has been replaced
    Are you saying the standby oil temp is 160*? If so, it's at least 25*F hotter than it should be. Turn down the oil heater thermostat to maintain 130-135*F during shutdown. If you replaced the equalizing line solenoid did you buy the part from JCI? Did you install it "backwards"? (Arrow on the body pointing opposite the direction of flow?).

  7. #7
    Join Date
    Mar 2004
    Location
    eastern north carolina
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    yes the solenoid is energized & arrow is pointing in the rite direction, standby oil temp was 140 deg. raised to 160 trying to
    solve problem, no help, will go back to 140. thank you for the input.

  8. #8
    Join Date
    Mar 2004
    Location
    eastern north carolina
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    80

    yt help

    at start up the oil level is in the middle of the top sightglass, but like i said before when the vanes start opening
    it looks like the entire oil sump turns into foam.

  9. #9
    Join Date
    Dec 2008
    Location
    Dixiana, AL
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    2,609
    This is another of those topics that is getting too deep for the open forum.

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