York YK Constant Surge?
Hey guys we have recently (around 3 months ago) had Johnson Controls install a R134a chiller along with a new project my building was doing. Ever since it was installed it surges in multiple counts and sits and idles and vibrates almost sounding like it is running dry. The VGD surge count is like 30,000 already. Not a pro on this one yet and we are still awaiting training on this chiller, but this thing sounds like **** and need something to tell the boss. Lol.
We are running on a lower load condition right now and the veins are fully closed. We have VFDs installed on our pumps (condenser and chilled water) and they are not at max. Please school me on what is going on this damn thing is keeping me awake!
I will include any points or temps just ask. Thanks.
Do you notice any movement of the VGD motor? Is there a VSD on this chiller as well? Is the system variable primary? Have you had JCI back to ask them what's going on? What temperature are you maintaining for condenser water? How about chilled water?
If you can post all your readings from when it is in this condition it will help. Sounds like a low load surge.
Stall is more like it. That's why I wanted to know what was going on with the VGD motor. If set up properly this machine should not be getting into a stall condition that it can't get out of. Lots of different things could be going on. I can't figure out why the factory wouldn't be called back in. If I bought a new car and it sounded like crap I'd be driving it back to the dealeer to find out what was going on.
Originally Posted by JEF1980
Welcome to rotating stall. If the guide vanes are not opening at all, get used to it or start a smaller chiller. The variable diffuser will help with low load stall, but if no load then the diffuser can only do so much. Lower the condenser water as well.
I will post the conditions. The project is not even finished yet and have yet to see anyone from JCI back in here in three weeks.
I was thinking stall. I will post all conditions. We eliminated a bunch of equipment that required cooling in the building so we replaced the old chiller with a smaller one. Well this is the smallest one we have. Lol.
Evap Sat temp diff- 1.2
Evap press- 36.4
Return liquid temp- 50.6
Leaving liquid temp- 44.1
Evap sat temp- 42.1
Return liquid temp- 79.4
Leaving liquid temp- 82.1
Outdoor air temp- 59.6
What is the design delta T for the evaporator? From what you are showing my guess is that you have a 12-13 degree machine in the evaporator and ten in the condenser. I think you are running the condenser water temperature far too warm. Lower it to 65 degress to start and see if that doesn't improve its performance.
Also does it have a variable speed drive? If so, it may have corrupted the surge map by now so getting it to slow down may be unreasonable.
Ok it stopped for now and is less often happening. They cranked the vfd on the condenser water pump down to 50% to reduce the gpm. For now it is ok. There is another guy coming in on Monday.
When I said "doesn't it have a variable speed drive" I was referring to the chiller. Condenser water flow is important, but temperature is a bigger factor. Lower the condenser water temperature under light load conditions.
Condenser water is to warm
If this is the case., time to start over w the map., hopefully JCI will do this for u., what water temp is recommended for this machine (condenser), 65 in ?
Originally Posted by KnewYork
blast'em man blast'em
!!!KILL THE TERRORIST!!!
I always encourage customers to run the condenser water at 65℉ or colder. In the winter I have some customers who will run the condenser water at 55℉. There is a law of diminishing returns so at some point it doesn't make sense to try to drive the condenser water any colder. If lowering the condenser water temperature gets the VSD equipped chiller to run at less than 40Hz, I say do it.
Originally Posted by mlkwal1