Johnson Controls YORK YLAA0189SE

Questions and Answers

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John AlexanderAug 11, 2025
What to do if Johnson Controls Air Compressor displays 'FLOW SWITCH OPEN'?
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  Crystal AndersonAug 11, 2025
  If the Johnson Controls Air Compressor displays 'FLOW SWITCH OPEN', it indicates there's no liquid flow through the cooler, the flow switch contacts aren't making proper contact, or the flow switch itself is defective. Ensure liquid pumps are running, valves are correctly set to allow flow, and the flow switch is functional and installed according to the manufacturer's instructions. On some systems, the pump starter may be wired to the unit and controlled to start by the unit. If necessary, replace the flow switch.
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Stephen NashAug 17, 2025
What to do if Johnson Controls YORK YLAA0189SE Air Compressor displays 'UNIT FAULT: LOW LIQUID TEMP'?
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  Andrea WeeksAug 17, 2025
  If your Johnson Controls Air Compressor displays 'UNIT FAULT: LOW LIQUID TEMP', it could be due to an improperly adjusted leaving chilled liquid temperature cut-out (especially for glycol systems), incorrect control panel setpoint/range values, low chilled liquid flow, or a defective sensor. Try re-programming the leaving chilled liquid temperature cut-out and re-adjusting the setpoint/range. Increase the chilled liquid flow. Compare the sensor against a known good temperature sensing device, ensuring it's properly installed with heat conductive compound. Refer to sensor calibration tables if needed.
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rrichAug 23, 2025
How to troubleshoot a Johnson Controls Air Compressor with no display on the panel?
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  Briana CrawfordAug 23, 2025
  If the Johnson Controls Air Compressor panel has no display and the unit won't operate, the main supply to the unit might be off, the emergency stop device might be activated, there might be no supply to -T1, no 24 Vac supply to the microprocessor board, no 24 Vac output from Transformer -T1, a short circuit in the wiring to temperature sensors or pressure transducers, or a defective microprocessor or display board. Switch on the mains supply if it is safe. Ensure the remote emergency stop device is in the ‘ON’ position. Check the wiring to -T1 and fuse -F1, and the wiring from -T1 to the J14 microprocessor board. Try changing transformer -T1. Unplug connections at the microprocessor board to isolate the issue. Replace the board after contacting Johnson Controls Service.
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Mason WilliamsAug 29, 2025
Why does my Johnson Controls Air Compressor display 'UNIT FAULT: LOW AMBIENT TEMP'?
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  Gloria JacksonAug 29, 2025
  If the Johnson Controls Air Compressor displays 'UNIT FAULT: LOW AMBIENT TEMP', it means the ambient air temperature is lower than the programmed operating limit, or the measured temperature is incorrect. Use the ‘OPER DATA’ key to display the temperature and confirm if the displayed value is approximately correct. The warning message should clear when the ambient air temperature reaches the programmed operating limit. Also, check the programmed settings are correct for the options fitted to the unit and verify the sensor calibration, location, and wiring.
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smithlindaSep 4, 2025
What causes 'UNIT FAULT: 115 VAC UNDERVOLTAGE' on a Johnson Controls YORK YLAA0189SE?
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  kevinflynnSep 4, 2025
  If the Johnson Controls Air Compressor displays 'UNIT FAULT: 115 VAC UNDERVOLTAGE', it indicates a poor mains supply voltage. Check that the mains supply is stable and within allowable limits. Also, check for any voltage dip when the compressor starts.