York YCRS Chiller

[fitter57]

I am a new member to HVAC-Talk I have been trying to find an IOM for a York YCRS 180 chiller this is a remote air cooled liquid chiller. The #2 compressor was recently replaced, after having a new slide valve installed with new spring. I was told the reason for replacement was slide valve stayed in same position. I just worked on yesterday. This compressor (new) reads between 62% & 68%. The #1 compressor will load up to 105% then unload to approx. 85%. Chilled water will not go below 49 deg. because of load of building. Setpoint is 44 deg. . I found SV steps on # 2 at 75 according to the book onsite this is fully loaded. I checked voltage output to the solenoid coil for the slide valve and had 12 vdc. I pulled the so;enoid coil off of the post and machine doesn't unload. I have a few questions. #1 How does the microprocessor get the SV steps? I don't see any kind of feedback to the board so I can only geuss that its some kind of cumulative value of the load signals given to the solenoid. #2 If this is true how does it lower, does it subtract when given an unload signal? #3 Does anybody possibly have the IOM or any service bulletins for this machine that they could send me? I don't have too much experience on these machines most of my experience is on centrifugals. Thanks

[york56]

Compressor loading is from the microprocessor where it gets its signal based on feed back to the micro , fault conditions , chwt , rate of change all have an effect on it , that voltage is sent to the capacity control valve which regulates oil flow to the slide valve which in turn loads and unloads the compressor no signal to capacity control valve then the internal spring on the slide valve would force it to close unloading the compressor.

[klove]

#1 How does the microprocessor get the SV steps? I don't see any kind of feedback to the board so I can only geuss that its some kind of cumulative value of the load signals given to the solenoid.
It is a % based on load signal, not actual SV loading

#2 If this is true how does it lower, does it subtract when given an unload signal? Same way in reverse

#3 Does anybody possibly have the IOM or any service bulletins for this machine that they could send me? If you have a book that tells you that the load signal is 12VDC, then you probably have the IOM. There are no actual service manuals on air-cooled gear

.

[fitter57]

Klove,
Thanks for your reply. The book they have on site is for a YCWS. It has a commisioning section but is very vague in its information.

Thanks Fitter57

[klove]

Trust me, the IOM for the YCAS is vague, too. If you'll get the full model number of the chiller posted, I believe we can get you what you need. They're too big to be sending multiples if not necessary. The basic operation of the air or water cooled are the same, though, as far as control schemes go, and the mechanics of the system and compressors.

[fitter57]

Klove,

Thanks again for the reply. I can probably work it out with the YCWS manual. I have been seeing some past threads about unloading problems with the DXS compressors. Do you have any service bullitin information about these.
Thanks-Fitter57