Lead Engineer

[JWeigelt]

We have a York Centrifugal Chiller Model YKFBFBH5 using refrigerant 134a - there seems to be some discrepancy on the proper condenser water inlet temperature for this chiller. We have experienced some surging in the past and the manufacturer said to maintain approx. 65 degrees on the condenser water inlet to avoid surging. Does anyone have experience on the proper temperatures to maintain with this type of chiller with 134a?

We are planning on installing 4 new chillers (York Model YK) and the condenser data indicates a range of 82 to 91 degrees F. Any ideas??

[mahmoud4871]

1- This range 82 F in and 92 F out should be at full load 100%, So if the FLA is 70% this 10 degrees DT should decrease to 7 degrees F. and 65 degrees on the condenser water inlet is low if you are running at night and the load is high.
2- Surging could be due to other reasons, such as low refrigerant charge, less condenser flow rate or un calibrated IGV, so you have to be sure it is high pressure surge and not due to other reasons as mentioned above.
3- Check for the HP while the surge is occurring, check and measure DT across the condenser and compare it to the FLA, this will give you indication of the good GPM on the condenser and also for the evaporator.
4- If the surge still on, you may need also to check for scale on condenser tubes." Adjust condenser water GPM and check DT " to be able to determine if the condenser tubes got scale.


Remember that surge is very dangerous to centrifugal compressor specially if it is YORK because from my experience with this type of chillers YK it never last with frequent surge and quickly damage the high speed thrust bearing.

[centrifs]

JW, you didn't state what series chiller this is, it is the last letter in the model number. There should be 4 more digits in the model num. Is it a vsd chiller or SSS??
I think from the series E on they claim you can run as low as 60*F cond. ret. with the refrigerant level control. Surging could be a lot of things, Hi end surge and Low end surge are 2 completely differnt animals.
You need a full log of this machine up in the 75-100% of FLA. Verify all press and temps also.

[fridgemonkey]

One thing about York, they had the surge detection box on some machines, which was measuring current. I have found out that after some 5 yrs those boxes are malfunctioning, probably dry capacitors, and surge trips are not surge trips... This goes for chillers made in France...Box was called "compressor pumping safety" on the diagram.