Another YCAS thread

[heavymetaldad]

YCAS0208EB17
Anyone be kind enough to forward or post the IOM? Just spent alot of time going thru 76 threads of YCAS topic, and not 1 IOM. I'd like to read up on this unit, saw on Friday in the faults '2 Wye Delta ON'. Both compressor were running. Was told by building engineer unit did not need reset (?)
Thanks, bOb.

[york56]

Here you go dude.

[heavymetaldad]

Thank you.

[heavymetaldad]

YCAS0208EB17
Saw on Friday in the faults twice was '2 Wye Delta ON'. Both compressors were running. Was told by building engineer unit did not need resetting (?)
Thanks, bOb.

Well, that fault is not in the book. I would think that an aux. contact was made that should have been open when compressor was off.
Any input / ideas?

[cperk]

Well, that fault is not in the book. I would think that an aux. contact was made that should have been open when compressor was off.
Any input / ideas?

If your in the fault history, you might have scrolled the wrong way. It shows everything the circuit is doing at the time of the fault, ie. wye delta on, llsv open, fan stage whatever, and so on. Hope this helps. Could have been just a power failure and the first thing that shows up in the history if scrolling the wrong way is sys 2 wye delta on.

[york56]

There are three contactors 1 small 2 large can't remember for sure but check small contactor to see if there is interlock contact because on start thats engaged then drops on transition and both large are engaged and I believe that one of those has a interlock contact also possible that small one is still engaged once that contactor drops out , haven't seen this fault.

[heavymetaldad]

If your in the fault history, you might have scrolled the wrong way. It shows everything the circuit is doing at the time of the fault, ie. wye delta on, llsv open, fan stage whatever, and so on. Hope this helps. Could have been just a power failure and the first thing that shows up in the history if scrolling the wrong way is sys 2 wye delta on.

First time I've seen this version of millenium. Don't believe I scrolled it incorrectly, but I may be wrong. Thanks for the input.

[heavymetaldad]

There are three contactors 1 small 2 large can't remember for sure but check small contactor to see if there is interlock contact because on start thats engaged then drops on transition and both large are engaged and I believe that one of those has a interlock contact also possible that small one is still engaged once that contactor drops out , haven't seen this fault.

I won't be heading back there soon, but I will keep it in mind.
Interesting you haven't seen this fault - but it was in the stored history, twice, although bldg. engineer stated that the machine was not reset. (could be not the complete truth)
Thanks for the input,

[york56]

Just looking thru the service book what may have happened is this micro calls for compressors to start turns on relay outputs (wye delta on ) compressors attempt to start but no 3 phase is on times out then faults micro logs fault then power is restored machine then restarts micro is most likely auto restart chiller back on line and running just a guess but makes sense look at page 20 in this IOM it explains the start sequence very well that interlock that I was talking about is not what I thought it was its for interlocking the contactors together.

[Ph-D]

Our THANKS to YORK56, your thoughfulness in posting the IOM is greatly appreciated. We take this opportunity to express our Thanks.

[heavymetaldad]

That is a great explanation.
Thanks again for the pdf, and the insight

[york56]

Some machines have single point power some don't the ones that don't the 120 volt control circut would be energized even when the 3 phase isn't which would give you this condition.

[heavymetaldad]

Not sure how it's configured, although loss of 3 phase power would have rung some bells and blew whistles.