YORK YK — LCSSS - 105% motor current overload

The control center shows LCSSS - 105% motor current overload; the other manual for this chiller prints the same message in capitals as LCSSS - 105% MOTOR CURRENT OVERLOAD. It belongs to the liquid cooled solid states starter safety fault messages and it is a safety shutdown, so the compressor is stopped rather than left running with the overload present. If the panel is showing a different message, the manual directs you back to the starter fault message list.

The highest of the three phase RMS currents has exceeded 100% FLA × 1.05 — put another way, the highest phase of the compressor motor current rose above 105% of the programmed 100% chiller FLA — and stayed above that level continuously for 40 seconds. Once the overload current is maintained for those 40 seconds, the starter trips this safety shutdown.

• The programmed FLA is incorrect on the OptiView™ control center.
• The output CT's are not reading current correctly.
• The output current is unbalanced.
• The pre-rotation vanes or the slide valve are not working properly.

1. Verify that the FLA programmed into the OptiView™ control center is correct.
2. Verify that the output CT's are reading current correctly.
3. Ensure that the output current is balanced.
4. Verify that the pre-rotation vanes or slide valve are working properly.

• Trip level: the highest phase of the compressor motor current must rise above 105% of the programmed 100% chiller FLA, which the manual also expresses as 100% FLA × 1.05.
• Trip delay: the current has to stay above that level continuously for 40 seconds before the safety shutdown occurs.
• The FLA reference is a programmed value on the control center, and an incorrect programmed FLA is one of the listed possible problems.

This trip is a safety shutdown: the SCR gate outputs turn off, a coastdown starts — 150 seconds on this centrifugal chiller — and the K1 relay de-energizes. After the coastdown times out, place the Compressor Switch in Stop/Reset, then Start and release; the chiller will start if no faults are active. The other manual describes the recovery from the display side: The chiller can be started after the Clear button is pressed next to the listed event on the Systems Details screen.