View Full Version : yt help
10-11-2012, 07:19 PM
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?
10-11-2012, 07:34 PM
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.
10-11-2012, 09:32 PM
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
10-11-2012, 10:35 PM
Solenoid has been replaced, but is it being powered and working. Had similar issue that the relay was bad.
10-11-2012, 10:53 PM
What's your oil level at startup?
10-12-2012, 12:54 AM
the shutdown is 160 deg, running temp is 125 deg.the foaming starts when the vanes start opening, the vent line solenoid has been replacedAre 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?).
10-12-2012, 02:37 PM
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.
10-12-2012, 02:40 PM
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.
10-12-2012, 06:54 PM
This is another of those topics that is getting too deep for the open forum.
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