On the display
The panel shows LCSSS - High phase A, B, or C heatsink temperature. The same text is printed in the safety fault list and in the Display messages list; in the display list the manual prints it with the unit state appended, as LCSSS - High phase A, B, or C heatsink temperature - Stopped.
What it means
The LCSSS logic/trigger board of the liquid cooled solid state starter has measured an excessive temperature on the silicon controlled rectifier (SCR) module of phase A, B, or C. Two situations are described. While the chiller was running, the safety tripped because the phase A, B, or C SCR module temperature exceeded 212°F (100°C). With the chiller stopped, the message is shown when the phase A, B, or C SCR module temperature is greater than 110°F (43.3°C); the starter cooling pump runs and the chiller is inhibited from starting until the temperature decreases to less than 109°F (42.8°C).
Why it appears
- The temperature of the phase A, B, or C SCR modules exceeded 212°F (100°C) while the chiller was running, as detected by the LCSSS logic/trigger board.
- With the chiller stopped, the phase A, B, or C SCR module temperature is still above 110°F (43.3°C), which keeps the message active and the start inhibited.
Setpoints and thresholds
- Trip level while running: phase A, B, or C SCR module temperature above 212°F (100°C).
- Safety reset level: all SCR temperatures below 210°F (98.9°C).
- Start enable level: all SCR temperatures below 109°F (42.8°C).
- Stopped-state message level: phase A, B, or C SCR module temperature greater than 110°F (43.3°C).
- Starter cooling pump: runs during the shutdown until the SCR temperature is less than 109°F (42.8°C).
Reset and restart
The safety cannot be cleared immediately; the SCR modules must cool down first. The manual states: the safety can be reset after all SCR temperatures are less than 210°F (98.9°C)
. One manual describes the reset as pressing the CLEAR FAULT key on the display; the other as pressing the Clear button next to the listed event on the Systems Details screen. Even after the safety is reset, the chiller cannot be started until all SCR temperatures are less than 109°F (42.8°C). During the shutdown the starter cooling pump runs until the temperature is below 109°F (42.8°C); at that point the message clears and the chiller can be started.
Questions engineers ask
What does LCSSS - High phase A, B, or C heatsink temperature mean on a YORK YK?
The LCSSS logic/trigger board measured an excessive temperature on the solid state starter SCR module of phase A, B, or C — over 212°F (100°C) while the chiller was running, or over 110°F (43.3°C) with the chiller stopped.
How do I reset the LCSSS high heatsink temperature safety on a YORK YK?
Wait until all SCR temperatures are below 210°F (98.9°C), then press the Clear button next to the listed event on the Systems Details screen; the other manual describes the same step as pressing the CLEAR FAULT key on the display.
Why won't my YORK YK start after the LCSSS heatsink temperature fault?
Starting stays inhibited until all SCR temperatures are less than 109°F (42.8°C). The starter cooling pump runs during the shutdown until the temperature falls under 109°F (42.8°C).
When does the starter cooling pump stop after this LCSSS fault?
It runs throughout the shutdown until the SCR temperature is less than 109°F (42.8°C).
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