York YT chiller. Oil in refrigerant?

[hvactech0]

I have a York model YT 500 Ton chiller in my facility. It has been retrofitted to r-123 refrigerant. I have recently noticed that the refrigerant sight glass is brown and a our oil is missing from the oil sump sight glass. The Johnson Controls techs and I added refrigerant since it was low on charge. The chiller has been running with a load for about a week and a half and little oil has returned to sight glass. I isolated system and removed the eductor and found it to be a little ubstructed. Cleaned it and the piping connected to it and noticed little oil recovery, but that was two days ago. Is there a certain amount of time it needs to recover the oil or is there something else we can check? Thanks.

[spinning wheel]

If the oil has fouled the refrigerant in the cooler too much, then you may need to remove the charge and distill the refrigerant. I would suggest removal of the refrigerant, find and repair the leak, then recharge with distilled refrigerant that was removed. You can also check the amount of refrigerant that was in the unit at this time. This may seem like alot of work, but it is quicker than waiting on the eductor and gas velocity to return the oil.

[hvactech0]

Yea i am bringing the Jci techs in to see what they can do. I am thinking shaft seal problem. I will test the pressure.

Edit. Shaft seal only protects from atmospheric.

[jayguy]

perhaps you are just low on oil. what are your operating conditions (pressures/temperatures/etc)...ALL OF THEM!

[hvactech0]

Ok I hate dealing with johnson techs! I will post all pressures and temps later. I decided for the hell of it to put a gauge on the seal. I measured 10" before startup then after startup I only measured 0lbs. I know that the oil seal should be between 2-4lbs. So I think that once this machine is sitting (other machine running or heat exchanger running) the oil is pulled into a vacuum into the refrigerant. Am I correct?

Oh and oil sight glass is only bottom full on shutdown all day. We added to get to one and a quearter. but it is back to bottom sightglass full. Loosing it into the refrigerant.

[DITAW]

when you added oil was it running or off when the level went down was the oil pump on or off, need alot more information.

[jayguy]

...Oh and oil sight glass is only bottom full on shutdown all day. We added to get to one and a quearter. but it is back to bottom sightglass full. Loosing it into the refrigerant.

if you have oil in the sight glass...why are you worried about the oil level? the oil pick up is at the bottom of the oil sump. are you losing oil presssure and tripping the unit off-line?

[hvactech0]

Sorry our refrigerant sight glass was brown not clear like it supposed to be, the veins have to run 94% to maintain load and that does not even get us down to setpoint. No tripping on oil pressure, but like i said i measured 0lbs of pressure on the seal. We added oil to protect the machine while trying to bring the oil out of the refrigerant while shut down and oil drained down for a day.

[jayguy]

time to stop adding oil. if you have operating conditions that cause the oil to leave the oil sump and hang out in the refrigerant system, then adding oil (instead of finding and fixing the condition) will only make it worse.

getting us those operating condition numbers would really help.

[hvactech0]

We only added about a gallon or two to keep oil in the sump. I will update you guy on what the jci find.

[sargent york]

Check the foul gas check valve, if installed backwards or not sealing it will slowly lose oil during fill cycle to condenser. There is even a very small posiblity that cooling coil in purge tank has leak. Oil return usually works well on YTs if refrigerant charge is high enough to splash over into oil trough where eductor can pick up and return to sump. Seal oil pressure has nothing to do with oil loss, it is to be set at @2#s. If too low or too high seal will wear out early.

[hvactech0]

Hmmm ok some good things to check. So oil cannot cross through the seal to the refrigerant? In the book it looks as if it can.

[chillerparts]

When the chiller is running above 75% fla, (sounds like it is at 94%) what is the evaporator leaving water temp and the evaporator refrigerant temp? If this is the old single line panel, you will have to use the display data key to get the info. Much easier on the Opti View Panel. Let us know what those numbers are. Get the seal pressure in a slight positive during the run. Is the purge pressure changing during run time?