Another ycas question

[87lt1monte]

I have noticed all the ycas threads in here but have a couple questions... I have a ycas250. 2 compressors will not load current is 54% slide valve steps are 75. One will load up but I had a problem where I shut this circuit down to see if the others would load and they would. Turn comp 1 back on and it goes out on motor current . I'm guessing because it's trying to start loaded. My question is what will prevent the comp. From loading? Pressures and temps are normal but I did find a bad discharge temp sensor on one that will not load.

[cheelr]

If the slide valve step is 75 the compressor is (at least as far as the micro knows) fully loaded. Problems could be the position indicating pot is out of cal (doubtful if two compressors on the same unit are acting similar) or the motor is only seeing 54% FLA with the slide valve wide open. Maybe cold condenser/outdoor temp with unit off for awhile and warm chilled water to start? Suction pressure might be running a little low also if this is what's happening, you need to get a little heat built up in the condenser (keep trying) before the evap can get a good flow even if the xv is open wide. If you're low on gas that won't help either.

The slide valve should spring return back to 0 steps after the compressor stops within a few minutes I think, you can check on the micro display whether it's fully returned to zero steps to determine if your re-start MP trip is being caused by it not being closed.

[87lt1monte]

I guess my question is at54% I'm pretty much fully unloaded right? I guess I will have to check to see if the solenoid valves are getting the right signal.. All 3 compressors were at step 75 only one was loaded.. I never get a fault the chiller water gets higher as the load increases throughout the day

[cperk]

I would start with the voltage to the cap. control. If that is correct replace capacity control. I've seen these stick unloaded also.

[klove]

First confirm that you are at or near the readout amps with actual amps. If so, check your voltage to the cap control solenoid as C said. 75 steps should be 10-12 VDC. Make sure your oil filter differential is not too high, indicating a blocked oil filter. Change filter if it is. Still won't load? Check voltage at the valve terminals to make sure no broken wires, then change the valve if volts are OK before doing anything really major.

p.s. DXS compressors don't have a slide valve position indicator (potentiometer).

[87lt1monte]

Thanks for all the help fellas I made it back to the job and my voltage to the solenoid valve was 16+. the book didn't say what to do if voltage was to high. I check voltage feeding the board .. 12vac.. I Swaped the slide valve plug for the compressor that was working to one that was not and the compressor still didn't load..

[servicetech 32]

I think this has been covered on another thread so you may have already gone down this road but did you get the information about compressor load troubleshooting? Your problem sounds similar to two compressors that I repaired a year or so ago. One needed a slide valve spring and the other needed external oil routing. Both work fine now. As I recall one was stuck unloaded and the other was stuck fully loaded. Let me know if you need the information and I will dig it up.

[RichardL]

As the wise ol' Klove pointed out, these compressors have "NO" idea where the slide valve actually is.....The panel knows "Only" where it told the slide valve to go....If it is not there.....Well..you know someting is not "Sliding" as advertised.....Control valve first suspect if adequate oil pressure is there...New & greater return spring when all else fails....JMHO

[largetonnage]

log in and check your VDC proportional signal setting from the motor protector to the micro. you should see something like 3.14 = 125%. just like Klove said, confirm actual and set proportional vdc accordingly. I've seen these lose the program in the past and this setting reverts to default. just something to try. good luck.

P.S.
I have twelve of the Ycas machines, and have never had any serious problems except one comp. change, good luck or good service??????????????????????????????

[chillerguy81]

P.S.
I have twelve of the Ycas machines, and have never had any serious problems except one comp. change, good luck or good service??????????????????????????????

I only have one YCAS in my herd and so far it's been running strong. I've talked with a few of the local Jork guys that I know, and they said they don't run into many problems with them. I've seen losts of YCAS horror stories on here, we must have better luck with them in Pa!