On the display
The control center displays Thrust bearing - Limit switch open. The Fault Acknowledge entry for this fault is on the System Details Screen, which you reach with the navigation buttons of the OptiView Touchscreen Control Center. The manual groups this message with the safety fault messages.
What it means
The high speed thrust bearing limit switch contacts, connected to TB3-81, have opened. This happens when the bearing position has decreased to less than the allowed position. The message applies only to compressors that use a sacrificial limit switch for thrust bearing protection; on compressors without this switch the message does not appear.
Why it appears
- The high speed thrust bearing limit switch contacts connected to TB3-81 opened because the bearing position decreased to less than the allowed position.
What to check
- Have a qualified service technician evaluate this shutdown before the chiller is started again — the manual marks this requirement with a CAUTION.
- Check that the thrust bearing limit switch contacts connected to TB3-81 have closed, since restart is inhibited until they have.
Reset and restart
The message is not cleared with an ordinary acknowledge. A special password is required to acknowledge the fault on the Proximity Probe Calibration Screen first. The message is then released when the chiller is in a stopped state and the Clear button is pressed next to the listed event on the System Details Screen.
CAUTION: a qualified service technician must evaluate this shutdown before starting, and restart is inhibited until the switch contacts have closed and a special reset procedure is performed by the service technician
.
Questions engineers ask
How do I clear the Thrust bearing - Limit switch open message on a YORK YK?
A special password is required to acknowledge the fault on the Proximity Probe Calibration Screen first. Then, with the chiller stopped, press the Clear button next to the listed event on the System Details Screen to release the message.
What is the thrust bearing limit switch connected to on a YORK YK?
The high speed thrust bearing limit switch contacts are connected to TB3-81. They open when the bearing position decreases to less than the allowed position.
Why won't my YORK YK restart after a thrust bearing limit switch shutdown?
Restart is inhibited until the switch contacts have closed and a special reset procedure has been performed by the service technician. A qualified service technician must also evaluate the shutdown before the chiller is started.
Does the thrust bearing limit switch fault apply to every YORK YK compressor?
No. The message only applies to compressors that use a sacrificial limit switch for thrust bearing protection.
Messages next to this one
Source
Written from the manufacturer's manuals for the YORK YK; every number and designation on this page is checked against them before publication. The row of the manual this message comes from:
All YORK YK messages: fault codes · YORK YK documentation · YORK manuals