• Member Post posted an update

      June 24, 2025

      I have a Trane RTAC that both circuits are having High Oil Temperature alarms. I did find a bad condenser fan motor om circuit 1. All the fans on circuit 2 are working and spinning the correct way. What else can be causing these high oil temperature alarms? The chiller is not staying online. The coils look pretty clean, but I will give them a rinse. How can I troubleshoot these high oil temperature alarms?

      Member Post and Member Post
      4 Comments
      • The oil temperature supplied to the compressor, exceeded 200 F for over 10 seconds.

        Check to see that the female step valve is stepping in
        Check for refrigerant overcharge using subcooling curves
        Check for excessive pressure drop across the condenser
        Check for non-condensibles

        2
        • I would check and make sure the oil sensor is reading correctly first.

          Does yours have an oil cooler, or no?

          A if you can send us a notebook with your readings, we could all help you out faster

          1
          • if you have an oil cooler, start there first (and check your temp sensors). I’m not that familiar with the RTACs I’ve only seen a handful, but if it uses CHW in the heat x, flush that and verify good flow through it.

            • Where are you located? What is the ambient temperature? What kind of chilled water setpoint are you running? If you’re running glycol and low chilled water temperatures, you will need to add oil coolers.

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