York YTH chiller

[bowhunter21]

Hello All,

Got a interesting problem with a york centrifigual and want to see if anyone else seen this and can give me some input. Anyway got a York YTH with a variable speed motor that does not seem to load. When the motor is at 60hz and the guide vanes (PRV) are at 100% here is what I got..... saturated evap refrigerant temp is 67 degrees, 23 evap approach, 10.3psia evap pressure, 38% motor current, 174 discharge temp, the condenser liquid level is 0% with a 50% setpoint and the evap is flood with liquid refrigerant. As the chiller runs the chilled water temperature continues to rise. It seems like the chiller is not moving any refrigerant at all. I disconnected the vanes and manually opened and closed the, it feels like the vanes are still moving but cant really tell unless we take off the suction elbow. Anyone have any ideas?

Thanks in advance

[klove]

Do you have multiple chillers in this plant? What are your chilled liquid temps? Do you have a negative or reversed approach on the evap? At 23* approach and 67* sat evap temp, your chilled water would have to be leaving at 90* to have a 23* standard approach temp. If you have a 23* negative approach and a setpoint of 44* or thereabouts, that means that you have a control panel that's keeping you unloaded because it thinks the setpoint has been reached or exceeded (I'll leave the "why" to you). With a non-reversed approach, it looks like you have some vanes that aren't opening, assuming that nothing in the control panel is lying to you.

Would it be possible to get one of the mods to move this to the pro forum?

And could pro members quit asking in-depth technical questions in the open forums?

[Tech Rob]

Is this one of the ones with a variable orifice? Is it all the way open? I think it should be with the conditions you describe. Low motor current, high evap approach, high discharge temp made me think low charge right off the bat. Then I thought about it more, and maybe you're on to something with your vane theory. If you have disconnected them before and moved them, you should know if something doesn't feel right. I've played with a couple of YTs, but most of my limited experience is with Tranes. They have a characteristic sound when they're running with the vanes closed all the way.

What are the entering/leaving chilled/condenser water temps? Sounds like the water temps could be inverted?

[jayguy]

with approach temperatures in the 20's on both sides of the chiller, closed vanes (or nearly closed vanes) is unlikely even with dirty tubes.

[DFZ]

check prv operation and calibration, check level probe calibration ( its says 0% but where is it for real), also check the level control valve, if the probe reads zero with a 50 setpoint it will be closing off to raise the level and make it 50 starving the evap.

[jayguy]

sorry...brain fart...i forget that the first thing that most people do is ask questions rather than check the accuracy of the sensors before posting the numbers.

PLEASE VERFY THE ACCURACY OF ALL NUMBERS BEFORE POSTING THE NUMBERS!!

[RichardL]

C'mon guys....How many Yorks running full speed with an evaporator flooded w/refrigerant and the PRV's @ 100% that would not overload in the extreme???
His vanes just ain't opening and thats a fact. Any additional information would be nothing but window dressing on this one. Pull the suction ell and verify the vanes being non-functional for whatever reason. Then get ready for some serious rigging. Any more information would be a mute point.

[jayguy]

so, 20F evaporator approach would be a common thing with the PRV's closed? what do you think the evaporator approach would be if he fixes the vanes and then PRV does open up? 30F? 40F? 90F? nope. as the chiller loads up, the evaporator and the condenser approach temperatures will go up, period. (i put a period at the end of the sentence to help state my seriousness of the word period! )

granted, there hasn't been a testament to the fact that all posted information has been verified as accurate, but since we are SWAGing anyway, i am guessing that the approach temperatures are pretty close to accurate. the displayed values of the PRV and liquid level sensors could be off but i think that they are a minor issue here.

no (or very little) refrigerant = no load = no overload. that's my SWAG and i'm stickin' to it!

[bowhunter21]

Good thing I verified all the sensor readings before I started asking questions or I would just be another statistic for jayguy!!!!!!! DFZ- the control valve does start to modulate close to bring the level up in the condenser but the evaporator is flooded and the condenser has no refrigerant at all. When you look into the condenser sight glass all you can see is a slight fog of refrigerant. I am waiting for a new shoulder bolt to come from York, which was a whopping $133. When I had the machine online for a extended period of time the purge was inactive. I think my next step might be to pull that suction elbow and check the vanes which would take care of several steps anyway, 1- verify the charge, 2- check the vanes and 3- get rid of any air if any is present. Hopefully a win, win, win. Can not get back to the site till next Monday I will keep everyone posted. Thanks for the input

[klove]

So you do have 90* leaving chilled water temp....

[jayguy]

Good thing I verified all the sensor readings before I started asking questions or I would just be another statistic for jayguy!!!!!!!...

it was not meant directly to you nearly as much as it was to everyone else but then again, considering the crowd around here that is likely to respond, perhaps we all need to make sure that our findings are verfied AND STATED as such.

how do you know the evaporator was flooded? the evaporator sight glass or that it is supposed to be flooded?

[sargent york]

If vanes are OK? Is the drive motor turning the right direction?

[bowhunter21]

I didnt take it personal JayGuy sorry if it came across that way. I looked in the evaporator sight glass and could tell that the evap was flooded with refrigerant. I thought it was empty as first but after taking a closer look while the machine was online I could tell that it was full.

[jayguy]

23F evap approach and you still have refrigerant in the evaporator? bad divider plate?

[Tech Rob]

I'm eager to read about the outcome of this one.

[MechanicallyInclined]

Something is way off. Are you sure all your temperature and pressure readings are ok? This chiller sounds all messed up. High Evaporator Approach and a full Evaporator?

[klove]

I'm eager to read about the outcome of this one.

I'm eager for the OP to answer the questions he's been asked.

[whatusi]

more than likely th prv however before you go to all the trouble of removing the suction. ell if this is a codekit or open drive. take a very close look at the coupling hub, motor shaft end and be sure the key hasnt fallen off and the motor is spinning the compressor but not at full speed. seen it same scenario.

[bowhunter21]

Sorry i have not had a chance to get back on, we are swamped at work. Anyway I will finally have a chance to get back down to work on the chiller on Monday. I was also waiting for a new shoulder bolt from York. All the readings that I posted were correct I verified them 4 or 5 times cause I too thought I was missing something. I will lwt you know if i find anything on Monday. Whatusi thanks for the idea about the motor key I will check that first.

[bowhunter21]

And the answer is............ so we found that control shaft for the pre rotation vanes seperated from the internal lever which was not opening the vanes. I replaced the control shaft and o-rings and all was good. The York iom gives great step by step instructions on how to replace it without removing the suction elbow. If anyone wants any more details just let me know. Thanks to everyone that helped out.