Trane RTAA 125 ton Rotary Chiller - Oil System Fault.

[Txcityengineer]

Hey everybody,

Newbie here.
I have two Trane RTAA 125 ton Chillers looped in parallel. We are having our condenser coils replaced with new ones as they were very deteriorated as we are near the coast. Here is where the problem begins. Both chiller ( which have two circuits each) were running fine with no faults before removal of coils. After coil replacement on one chiller, I'm getting a Oil System Fault on both circuits of that chiller. They run for about 30- 45 minutes before they shut down on this fault. This fault has never shown up in the (5) Five years I've been here. All sensors were good before and still appear to be working fine. The condenser fan staging has been checked as well as the heater circuits. Has anyone ever run into this problem? OR does anyone have any suggestions? I'm just trying to help these guys what I can. They've been to TRANE, and not a lot of help from them. No parameters were changed for this install. They did say that it was low on R22 on ***** on one circuit and they added some.

[install monkey]

http://www.mediafire.com/view/8jqjebawp1e0bqy/RTAA-SVX01A-EN_09012005.pdf
service manual
check oil filter temp drop-
also drier cores are changed
also oil level in the oil seperators, crankcase hts work, and bear in mind the bottom 1/4 of the cond coil is for oil cooling

[FreezerGeezer]

Bottom or top, IM? Can't remember now which way around the RTAA's are. No matter which really. An IR thermometer is probably the fastest way of checking the oil separator level as long as the oil is warm. Let the circuit sit for 10-15 mins. (if it's running) before checking as otherwise it's very difficult to see the change in T*C which shows the oil level.

Check (if it's possible) the T*C diff's around the coils. I have known one instance of a brand new coil with a blockage.

[Grizzly]

Hi TXcityengineer.
Welcome to the forum.
As a guess, the extra efficiency of the condenser may be the issue?
So, if the temperatures you are now operating in are starting to drop.
Your oil issue could be a poor configuration setting?
If the condenser are side by side and it is the one of the 2 that is more exposed of the 2?
Then that would add to my theory, especially if both of the chillers are set-up identically?

If unable to check, try blocking off the lead end of the condenser with say cardboard sheet, to reduce the initial efficiency of the coils.

And see if the systems run for any longer, whilst running either option monitor the oil temps/ pressures displayed.

The RTAA has 2 condenser fan ambient fan configurations 15F or 0F.

If on the lower setting it may pay to raise the setting?

Good luck.
Grizzly

[moideen]

Hi TXcityengineer

what is the pressure difference between oil filter?oil pressure has relation with discharge pressure in screw chillers.provide all details such as discharge pressure,suction,ambient temperature.......etc

[Txcityengineer]

Thanks to everyone for all your suggestions!!

Waiting for the installers to return as it's the holidays, and the building will be closed part of the week. I learned today of a possible directive from Trane that came out some time ago about changing TXV valves and the control board on this particular model. I will post again when I have some of the answers asked, or when something changes.