YORK YK — LCSSS - Phase rotation

The panel shows LCSSS - Phase rotation; the control center service form prints the same shutdown as LCSSS - PHASE ROTATION. It belongs to the liquid cooled solid states starter safety fault messages, so it is a safety shutdown of the starter.

The LCSSS logic/trigger board has detected that the three phase compressor motor power line voltage phase rotation is not correct. The board checks the input phase sequence: when the “A” phase voltage transitions positive, the “C” phase must be positive; when the “A” phase transitions negative, the “B” phase must be positive. The check is only active during the first 30 line cycles after power is applied to the starter, so the shutdown appears when power is first applied.

• Phasing of the input power wiring is incorrect.
• The motor wiring between the LCSSS and the chiller motor is reversed.

1. Verify the phasing of the input power wiring.
2. Make sure the phase rotation is correct — the chiller can only be started after the phase rotation is correct.

• The phase rotation check is active only during the first 30 line cycles after power is applied to the starter.
• The sequence the board expects: when the “A” phase voltage transitions positive the “C” phase must be positive; when the “A” phase transitions negative the “B” phase must be positive.

Correct the phase rotation first — a wrong sequence keeps the shutdown active. On the Systems Details screen: The chiller can be started after the phase rotation is correct and the Clear button is pressed next to the listed event on the Systems Details screen. The service form for this style of chiller gives the equivalent restart path: after the coastdown period, restart via Compressor Switch Stop/Reset then Start, if the shutdown is no longer active.