View Full Version : Trane RTUA

10-16-2009, 09:44 PM
Ok guys, not much info but it was asked of me by a friend of mine over the phone today. He has an Trane RTUA (not sure what tonnage) which has an oil cooler on it coming from the separator. It is latching on a "high oil temp circuit 1". He said he changed the oil temp sensor, the chilled water modulating valve and checked the solinoid in the entering coolant line. He also said the oil level was within the range. I several questions so I hope someone can answer all of them:

(1) What should the oil temperture drop be through the oil cooler?
(2) What should the oil temperature be leaving the separator in relation to the discharge temperature?
(3) Could a clogged oil filter or master oil valve cause the temps to be higher than normal?

If anyone has any suggestions or ran into this it would be helpful. I don't run into these splits very often. Most of mine have remote evaps and I have had dirty condenser coils, but this one I have only seen in the field once. I know on the smaller tonnage machines Trane looks at oil temperature and saturated condenser temperature for oil flow rather than differential pressure switch, but this one I have NO idea with those oil coolers. If anyone knows of a Trane guide that shows the logic or troubleshooting oil temp issue's that would be even better.

10-17-2009, 01:30 AM

have we made sure all condenser fans are on and rotating properly?


10-17-2009, 09:58 AM
Had to start up 2 80 ton units this summer. Darndest thing. One had all it's pressure controls switched on the wrong circuits. Took a bit of head scratching and wire tracing to figure that factory mistake. Will take a look today to find the manuals.

10-17-2009, 10:23 AM
Check your fans and if condenser coils are clean. What's the ambient temp? Is this chiller process, or run during low temps? There are times if the female load solenoid drops out (completely unloaded) & is allowed to run like that for awhile, it will trip on oil temp. Is this a 2001 machine? Software changes allowed the female load solenoid to open for x time, in order to vent off discharge gas, which keeps the trip from happening.

10-17-2009, 11:58 PM
These were installed in 2006. Not sure about the fans, this unit has an oil cooler (compressor and evap are inside) 404a. I have had Rtaa do this but the oil circuit in the condenser was plugged. I am assuming that if I had fans or issues that would cause liquid issue's which feed this cooler