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One thing I'm still concerned about is the fact that these drives were retrofitted. Take a picture of the inside of the panel paying particular attention to the ACC board and post it. There is still a chance that the grounding isn't proper. Whenever I hear of maps getting filled up in a short period of time I think of corrupted data. I have watched an ACC board illuminating the surge lamp when there was no surging going on. Sometimes the lack of proper grounding can cause the problem.
. the only time it is bad is if the map is full of bad data...surges that occured due to some inaccurate data or some condition that no longer exists like air in the chiller or low condenser water flows...something major like that. Thx
Appreciate the help.
[QUOTE=murphman;13109541]Sensitivity already at 7000, no condenser bypass valves, no drive on tower fan and yes there is obviously some hunting on tower temps without drives. Is that alone enough to not let drive back off??? Optiview panel exists.[/QUOTE You may already know this but here goes, The chiller is going to try to drive the vanes open to 100% and then back the motor frequency down to a minimum of 30 hz to control setpoint, Although I have never seen one run at 30 hz that is the minimum. In low load situations when the drive has backed down as low as it can without surging it will have to shut the vanes to keep from overshooting the setpoint. When the chiller is running at low load the cooling tower can typically give you colder water than desired (condenser water setpoint should be 14 degrees above chilled water setpoint), so in your case the cooling tower fan cycles. When the chiller is running right on the surge line and then it gets a relativly fast change in condenser water temp it will not have time to react and probably surge. This is why you need to keep the condenser water temp steady or else you will fill the surge map up fast. One thing you can try that may work ok is to adjust the surge margin from 0 hz to 2 or 3 hz. This will make the drive run less efficient but will give the chiller more time to react before it surges and creats a surge point. Obviously the better fix would be put a drive on the tower and keep the condenser water temp steady but trying to talk a customer into spending more money can sometimes be difficult. Good Luck
Sensitivity already at 7000, no condenser bypass valves, no drive on tower fan and yes there is obviously some hunting on tower temps without drives. Is that alone enough to not let drive back off??? Optiview panel exists.
Originally Posted by murphman No drives on tower . Do you have a condenser water bypass valve?
I believe email/ westinghouse could have developed the movable diffuser, not that easy to set though back in the day, also think a lot of the problems could have been due to the float system, have seen a few retrofitted to PO. With the use of electronics etc maybe hopefully someone improving design.
Optiview or single line panel? Like Chad says set sensitivity to 7000.
No drives on tower .
Originally Posted by murphman Yep, several chillers with TM2 removed and retrofitted with new vfd's. Tower water consistently around 65-68, but do run low load from time to time. Surge maps detecting surges but seem to be stalls more than surges. Is the surge sensitivity set to low, also do your cooling tower fans have drives on them, if so are they holding a consistant condenser water temp or are they hunting? Everything in the system needs to be steady, no abrupt changes for the machine to run smooth.
Not sure what the question is Bklyntek. The purpose of the diffuser in the York high pressure centrifugal is to keep the compressor out of the stall zone. Transducer in the discharge measures slight pulsations in the discharge pressure and based on an algorithm moves the diffuser to narrow the gap for gas exiting the compressor.
Hi guys, bklyntek, going bck a few posts, is York's VGD point on chiller similar to carrier's. Just asking for clarification, seen carriers w/diffuser wall sensor. But at the was a new to the big iron systems, haven't worked on Carr. Chillers since. Seen more YCAS/R/W's and alittle of the MCQUAY units. I always try to keep to basic principles and has helped me tremendously over the years. Thanks again,it's always a pleasure.
Originally Posted by murphman ...Map loaded again, although it did back down at that time.....until map loaded up again. it sounds like many here think that a full surge map is bad...it isn't. you want it full. the map is a road map of where NOT to go. it is a map of tested areas that are not fun and to stay away from. the only time it is bad is if the map is full of bad data...surges that occured due to some inaccurate data or some condition that no longer exists like air in the chiller or low condenser water flows...something major like that.
My point is only that it was developed by Westinghouse. Cheers
Originally Posted by AiResearch Movable diffuser in discharge area = Westinghouse / McQuay And your point is?
Movable diffuser in discharge area = Westinghouse / McQuay
Have 3 machines retrofitted by JCI with new drives. Condenser water approx 65-70. extremely low load conditions....sometimes 47 degree entering chilled water, surge map full. Cleared it once, watched map start counting off surges. Couldn't hear anything even remotely sounding like a surge. I'm guessing stalls. Map loaded again, although it did back down at that time.....until map loaded up again.
Originally Posted by Rover So york developed the movable diffuser?, one reliant on oil pressure or electronics? Yes, the VGD or variable geometry diffuser has been in production for quite a number of years (I'm going to guess around 8 years...could be more). It's controlled by a transducer in the discharge volute. It senses small pulsations in the discharge gas. The control scheme is involved. The end result is that the machines are much more stable over varying load conditions. JCI bought York in 2005. The York product is still made, but I have the feeling that JCI will eliminate the York brand name sometime in the future. The company is that arrogant, IMHO.
Originally Posted by KnewYork I think you are confusing "stall" with surge. The tower problems would not contribute to the low load conditions of which you speak. The rumbling one experiences in low load conditions is usually not a surge, but rather a "stall" condition. The two are very different conditions. Surging occurs when actual head exceeds design head. A stall condition occurs when then refrigerant gas recirculates within the impeller and is unable to be pushed into the volute. After York came out with the YK series there were cases of stall that needed to be addressed. Stall can cause damage to the compressor/chiller as well. What York developed was the VGD or variable geometry diffuser. This diffuser closes the gap in the discharge wall to allow the refrigerant to get through the volute and into the condenser. So york developed the movable diffuser?, one reliant on oil pressure or electronics?, just curious, who knows what banner they are flying under now, got a few pe (westinghouse), 1972 design still going.
95% of times the chiller is blamed. Try checking for field related problems, (UNLESS york /jc r&d is not up to scratch)
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