York YK Oil Temp Problems

[CTI2010]

I have a York YK chiller, full model # is YKDPDSQ3-CKG. The problem I am currently experiencing is that the unit is generating a fault of High Oil Temp.

This fault is created when the oil temp reaches over 180. There is a brazed plate heat exchanger that controls the oil temp, fed liquid refrigerant directly from the condenser, through an expansion valve, and then into the evaporator through a ball valve. I watched it run for around 3 hours one day and I could see the oil temp climb slowly.

not much to the oil cooler, so I figured it had to be the expansion valve ( all of the refrigerant valves ARE open). I replaced the valve and monitored it for 2-3 hours. everything seemed okay.

Unit tripped the next day again.

Any ideas?

[KnewYork]

With machine running take accurate temperatures of the oil entering and leaving the oil cooler. Also take the temperature of the refrigerant return line to the evaporator. Post those here and maybe we can figure out what's going on. Are you maintaining a liquid level in the condenser? I think most of us would appreciate more information about yourself in your profile.

[CTI2010]

I have not monitored it since the last fault, but the oil temp leaving the cooler was around 6 degrees lower then the sump temperature from memory.... the exiting oil temp was 141-145 (going into the oil filter) and averaged 143.8 over a 50 min span (calculated from Fluke min/max setting). the sump temp at this point was around 149-150. in the 2-3 hours that I monitored the unit, the oil sump temp never went over 150. the unit was running balls out 100% FLA.

Oil pump was maintaining 37#, oil heater shows off... return solenoid shows open. Oil pump running at 45-47 Hz. Oil level in the "good" level of the sight glass, just about 50% mark. not low, not over filled.

I have been at this site since install. unit is around 3 years old. York performed factory start-up.

Annuals were due at the time of the call, so I started there to eliminate problems. New oil filter (canister evacuated), tubes brushed (no fouling).

[KnewYork]

If this machine is running at 100% FLA AND you are not maintaining a refrigerant level in the condenser I would suspect you aren't feeding enough refrigerant to the oil cooler. The refrigerant pick up is from the bottom of the liquid line if I remember correctly. If the VOV is wide open (i.e. no level in the condenser) you may have trouble feeding the oil cooler. There is no way (IMHO) you should ever see oil temperatures you are reporting in the sump.

Is your oil eductor working? The oil/refrigerant mixture returned from the evaporator also assists in oil cooling.

[nyrb]

On the oil side of the system you should have a 3 way AMOT valve that should be mixing hot and cool oil to maintain a feed temperature around 120 degrees. Take temp readings of entering oil to cooler, leaving oil from cooler and leaving oil from AMOT valve to ensure valve is functioning properly. Just something else to look at with that already mentioned.

[CTI2010]

I am not certain if it is. That was the next thing I was going to check on the unit. I noticed that this unit has a solenoid that appears to control the oil inductor and I was thinking that there could be a possible problem with the coil or control signal.

The condenser liquid level is just at the bottom of the sight glass on the condenser. This was also marked with a paint pen at start up with the charge weighed in (1,600 lbs) running at 100%.

I did not think to look at the oil return line because the unit was not having a problem with oil loss, it only occurred to me later.

there is an identical chiller next to this one that maintains 137 sump temp when running (it was a colder day and partial load). I was figuring perhaps 10 degrees higher might me normal since the unit was running 100% and warmer day since the oil heater is set to shut off at 160.

[CTI2010]

On the oil side of the system you should have a 3 way AMOT valve that should be mixing hot and cool oil to maintain a feed temperature around 120 degrees. Take temp readings of entering oil to cooler, leaving oil from cooler and leaving oil from AMOT valve to ensure valve is functioning properly. Just something else to look at with that already mentioned.

This was also something that I was told to examine after talking to a buddy of mine that was york factory.

I haven't had a lot of experience on the newer york chillers, epically the high pressure ones. (primary experience is with Carrier low & high pressure, Trane CVHE/F, and york low pressure. these are 2 of about 5 york high pressure machines I have worked on).

[york56]

If this machine is running at 100% FLA AND you are not maintaining a refrigerant level in the condenser I would suspect you aren't feeding enough refrigerant to the oil cooler. The refrigerant pick up is from the bottom of the liquid line if I remember correctly. If the VOV is wide open (i.e. no level in the condenser) you may have trouble feeding the oil cooler. There is no way (IMHO) you should ever see oil temperatures you are reporting in the sump.

Is your oil eductor working? The oil/refrigerant mixture returned from the evaporator also assists in oil cooling.

I would agree with statement I had one doing the same thing other guys had tryed to ajust txv but didn't help the problem , what I did do was calibrate the level probe after that the oil temp was more stable and lower. Before it would do exactly what you are discribing start out low and gradually climb once it hits its the trip threshold your done shutdown on high oil temp.

[KnewYork]

On the oil side of the system you should have a 3 way AMOT valve that should be mixing hot and cool oil to maintain a feed temperature around 120 degrees.

No 3-way (AMOT valve) on this design. Once the TXV was installed there was no need to bypass the oil cooler. All the oil passes through the cooler and depending upon the temperature of the oil, the TXV feeds refrigerant to the other side of the plate and frame heat exchanger.

The condenser liquid level is just at the bottom of the sight glass on the condenser. This was also marked with a paint pen at start up with the charge weighed in (1,600 lbs) running at 100%.

The level in the condenser when the chiller is running should be at about 1/2 the sight glass in the condenser. It is extremely important to keep the sub-cooler flooded. Run a trending screen on the liquid level at 5 second intervals and see what percentage is maintained. Let it trend for 20 minutes and see how steady the level is maintained. Before starting the trend see what the Optiview is reporting as the level. Depending on the skill level of the start up man there is a possibility the chiller was undercharged from the get go. (It wouldn't be the first time.) If you haven't worked on the level control or are unfamiliar with how it operates, I would suggest you read the service manual.

[CTI2010]

This makes sense, that is what I originally thought. I had traced out the piping and didn't see a bypass valve, but figured maybe I missed something.

I will check the level and set point when I return to the site.

Does anyone know the service log in codes off the top of their heads?

I know standard login is user id 0 and 9675

I have not used the service login in quite some time... I believe the last time i logged in under this setting I may have used the same used id of 0, and the code was something like 3785?

[KnewYork]

You really need to get a service manual for the Optiview panel. If you don't know the service password, how could you possibly be able to troubleshoot and properly adjust the level controller? You don't need a service password to set up a trending screen. Setting up a trending screen is covered in the IOM manual.

[nyrb]

Once the TXV was installed there was no need to bypass the oil cooler. All the oil passes through the cooler and depending upon the temperature of the oil, the TXV feeds refrigerant to the other side of the plate and frame heat exchanger.

Thanks for the update, haven't seen any with that configuration yet.

[CTI2010]

Turns out the problem was that the metering valve actuator was actually going out. New actuator is on order.

[KnewYork]

Turns out the problem was that the metering valve actuator was actually going out.

So that everyone reading along is on the same page...the metering valve actuator is what controls the butterfly valve (variable orifice) to maintain the level in the condenser. If the level in the condenser is not maintained it becomes increasingly difficult to supply liquid refrigerant to the TXV that is supposed to be controlling the oil temperature.

The high oil temperature was a symptom of another problem. As mechanics we need to be diligent in finding and treating the cause rather than the symptom. Even a casual look around the chiller while running one should have noted the subcooler wasn't flooded. No liquid stack, no liquid to feed the TXV.

I stand by my earlier statement regarding the service manuals. If you have been caring for these chillers for three years and do not have a service manual for the the Optiview panel at the VERY least, then IMO you are doing the customer and yourself a disservice. You need to read and understand the operation of the chiller and it's controls until it's second nature...that's what the customer is paying you for.

[CTI2010]

again, thank you all for the help. I understand what you are saying about the service manuals, but I do have copies of them, just didn't have them on hand at the moment. Yorks are not a frequent machine around here, or at least not many of the sites that I deal with. I have several units of information from york that cost over $500 for the literature, I just don't carry it on my because it is space that I can not afford to use up when I only have 2 units at one job site currently.
I was only at the site the one time when the unit had a Fault and the actuator was an intermittent problem. I could never get it to trip off on oil temp or climb over 150. I guess that is only one of the many reasons I can't stand York units. Of course I guess that is why they call them the low bid machines. These chillers are only 3 years old and have had more problems then any unit should in 3 years. especially considering that they only get 300-500 hrs a year of run time at the most.

[KnewYork]

I guess that is only one of the many reasons I can't stand York units. Of course I guess that is why they call them the low bid machines. These chillers are only 3 years old and have had more problems then any unit should in 3 years. especially considering that they only get 300-500 hrs a year of run time at the most.

Wow! York the "low bid" chiller? I guess you haven't been around very long. Yorks tend to be one of the more expensive chillers. And to pass off your lack of knowledge of the chiller because you don't have the room to carry the manuals is lame at best. Further, if you really understood chillers you would realize that a chiller that only runs 300-500 hours a year is a problem in itself.

I find it interesting that you come here asking for help and when it's offered up at no cost to you, you turn around and blame the equipment and not having the room to carry books. That sure is convenient. Deflect the problem to the equipment rather than take the time to learn and understand the problem.

If you want to pass along the name and address of the customer I'll see if I can get someone else to take the Yorks off your hands. BTW, did the customer have to pay for the TXV you misdiagnosed?

[CTI2010]

I am not passing off a "lack of knowledge". If you can say that you know everything there is to know about every chiller, then feel free. You would be the first I know to make such a broad statement. All I was saying is that free room on a service truck is limited, and I keep the material available that is in the highest need (benefits the majority of my customers), the rest stays in my office until needed (which is where I went when I needed it). I simply chose to look for help on the web until I was able to get the information.

Secondly, low chiller run time is not a problem in itself. On a low pressure machine I would agree with you that it is much more of a problem. I would also agree with you that YORK has one of the biggest problems with low run time because they have open drive compressors that have shaft seals to leak. They also have motors that are exposed to the elements along with varying temperatures. Carrier and Trane chillers have enclosed motors, which in my opinion are much better. I HAVE been in the trade for over 10 years and had a hand full of york chillers (maybe 15 or so), and they have always had the most problems (not major, just all of these stupid nuisance problems, such as actuator motors, electrical connectors, displays going out, leaking shaft seals, etc....) They also have purges that can't run when the machine is off. I could go on and on but there is no need to.

Third, to make a blanket statement about how long I have been around chillers in ridiculous. The fact of the matter is I was practically raised around them. I have been working on & overhauling chillers, and large tonnage recips for over 10 years. I provide my customers with support that most technicians will never come close to. It is why I have been in business for myself since I was 25. I have been through independent training programs, along with union programs. I am also a UA journeyman and have a Bachelors Degree in Business. This is a simple verse to live by COL 3:23 Whatever you do, work at it with all your heart, as working for the Lord, not for human masters.

And I would never charge a customer for a repair that did not solve the problem. Sometimes things like this, along with warranty calls, do happen. that is what profit is supposed to cover.

I learned early in the trade that there is nobody that knows it all. the important thing isn't knowing it all, it's knowing who to call when you don't.

[spinning wheel]

As a company owner, I would assume that you have a laptop at all times. Get with the times, everything is available in PDF format. I stopped carring paper books a long time ago. Even a thumb drive with this info on it, you could use the customers desktop.

Just a thought.

[CTI2010]

Yes. I do. I emailed my rep when i wrote the first post and received the pdf files yesterday late afternoon. They are now in my file.

[rahzip]

would also agree with you that YORK has one of the biggest problems with low run time because they have open drive compressors that have shaft seals to leak. They also have motors that are exposed to the elements along with varying temperatures. Carrier and Trane chillers have enclosed motors, which in my opinion are much better.

Yes,York has had problems with leaking shaft seals. However, their bellows style seal works very well. Providing the thrust is in spec. and the chiller does not surge excessively. It also helps if the chiller has the standby seal lube.

As far as the hermetic motors being "better". That is a matter of opinion.

I have torn down five Trane chillers (four Centrifugal & one screw) because of open rotor bars and been around several that need to be repaired. Disabling the restart timer on Tranes is not a good idea.

I can not speak about Carriers because I very seldom work on them.
I have never had to a rotor bar issue with a York.