Trane 90-Ton Commercial Chiller & Water Pump Inspection 08.25.26
Setpoint Services performed commercial chiller service and a chilled-water system inspection on a Trane Series R RTAA 90-ton air-cooled chiller in Austin, Texas. The service included inspection of the chilled-water pump and associated water-flow system while troubleshooting intermittent chiller shutdowns. The Trane RTAA0904YK02A3C0DF chiller had also experienced a “Starter Transition – Compressor A” fault that prevented Compressor A from consistently completing its starter and contactor transition sequence.
Troubleshooting of the Compressor A starter circuit led to replacement of all four auxiliary contacts associated with the compressor starter/contactor sequence. Following the electrical repairs, Compressor A successfully started and transitioned normally during subsequent testing, and the previous starter-transition fault did not reoccur.
Setpoint Services later returned for an after-hours service call after another intermittent chiller shutdown. Diagnostics determined that the new shutdown was associated with the chilled-water flow interlock rather than the previously repaired compressor starter circuit. The chilled-water system and flow operation were inspected, including the IFM SN0150 flow-monitoring relay and associated flow-sensor circuit. Testing identified an intermittent wire-break/fault indication capable of interrupting the chilled-water flow interlock and shutting down the 90-ton chiller.
The flow-sensor connector and pins were inspected and serviced, and the threaded connection was securely reseated and tightened. The Trane chiller was then restarted and monitored with both compressors operating normally while the chilled-water system continued pulling toward its 44°F setpoint. The intermittent flow fault did not return during testing. Additional repair of the flow sensor, connector, cable, or associated wiring may be required if the fault returns.
