York YT Chiller VFD Question

[tbirrd]

Hello, I am wondering what the driving factors are for a York YT Chiller (VSD-YTG3A4E1-CNJ) VFD to slow down? With very low load on the chiller, the compressor VFD output remains at 60 HZ. When load continues to decrease, the chiller shuts off on low leaving water ~5 times and eventually goes into alarm.

It seems like the compressor should begin to slow down for better load management as well as kw/ton performance?

When the chiller is half or more loaded, I do see the compressor slow down when condensor water is cold (mid-60's). However in low load situations, it doesn't seem to matter where I put the condensor water to get a VFD reaction. I notice kw/ton get worse with warmer condensor temps as expected.

Any feedback would be much appreciated.

Thanks

[DFZ]

sounds like a full surge map,

[r404a]

does sound like a full surge map, take this to pro chillers forum

[jpsmith1cm]

does sound like a full surge map, take this to pro chillers forum

The OP is not a Pro Member otherwise I could move the thread there.

Would it be better if I moved it to the open chiller forum?

[r404a]

yes, thanks jp

[KnewYork]

Well, Richard, if you knew your York model numbers you would realize that a "J" series YT comes with an Optiview panel. The admin code of which you speak is only needed to enter data on the "Sales Order" page as well as to alter the number of starts or run hours of the chiller. Admin codes are specific to the software and are good for the day they were issued.

There was no admin code for single line panels. There are codes that aren't published (and I know all of them), but admin codes didn't come out until the advent of the Optiview panel which is found on ALL "J" and "H" series York YTs. After working for York and then JCI for a total of 27 years I think I have a decent grasp of the product line especially the centrifugals.

[jpsmith1cm]

Moved to Open Chiller Forum.

[Russ57]

You might wish to read the following. The reasons are a little too complex to state in a forum. One could say reduce lift but there comes a point where chiller design places limits. One with all the bells and whistles should, and can, run down near 10% of rated capacity.

http://www.mcquay.com/mcquaybiz/lite.../AG_31_002.pdf

[RichardL]

If you have ever had a leak bad enough to create s surge condition, it would load the surge mapping with incorrect mapping which would inhibit the lowering of the output frequency. I woulod advise that you clear the surge map and let the beast start over again....Assuming you do not have a problem at the present time with non-condenseables.

[r404a]

richard

doesnt york need to be called in to clear the surge map due to password?

r404a

[RichardL]

richard

doesnt york need to be called in to clear the surge map due to password?

r404a

Yes they do....

[tbirrd]

Yes they do....

Thanks, I will bring this up to York. Is this map something that the chiller processor builds and adapts to ?

[RichardL]

Yes...It tries to find the best "Sweet Spot" for maximum eff. Sadly enough the "Sweet Spot" is very close to the surge locus. Once it detects a surge, it accelerates beyond that point and logs those conditions into memory on the ACC board. It is not uncommon for the chiller to log thousands of surges during its learning process. Sadly enough should a problem "Ever" exist with non-condenseables which could create a possible surge, the ACC board logs that possible perfect condition of vane position, motor speed etc. as a surge locus and will never accept that position again. To reset the "Surge Map", the factory must be contacted and a lengthy procedure with a York technician and the factory must be established to access the ever changing "Admin Code". Don't bother to memorize the access code he/her will use as it will only be good for a very short period of time. The "Admin Code" gives full access to all the deep logic stored in the B-Ram and could create havoc should someone mess with the core logic.